JP2612768B2 - Battery-powered excitation power supply for superconducting magnets - Google Patents

Description

The present invention relates to an excitation power supply for a superconducting magnet,
In particular, the present invention relates to a battery type excitation power supply for a super power supply magnet using a DC power supply as a power supply.

[Conventional technology]

As the excitation power supply for the conventional superconducting magnet,
For example, a stabilized DC power supply as shown in FIG. 3 is widely used.

The excitation power supply device shown in FIG. 3 converts an AC supplied from an AC power supply into a DC power and uses it as a power supply for the superconducting magnet 1, and includes a transformer 2, a rectifier circuit 3, a smoothing circuit 4, a control circuit 5, a current It comprises a sweep unit 6 and further includes a protection resistor 7 and a quench protection circuit 8.

Cryostat 10 is liquefied helium LH as shown
_d . Superconducting magnet 1 is immersed in _e
It is obtained by forming so as to cool with N _2. The superconducting magnet 1 is a circuit element having zero electric resistance and only inductance.

The superconducting magnet 1 has no Joule loss in a state where a constant current is continuously flowing in a steady state, but a power source must supply power corresponding to the product of the back electromotive force and the current during excitation. On the other hand, during the demagnetization, the energy stored in the superconducting magnet 1 is returned to the excitation power supply. Therefore, at the time of excitation / demagnetization, the output current value from the excitation power supply must be varied stepwise.

For this reason, the conventional device converts the AC input to DC through the transformer 2, the rectifier circuit 3, and the smoothing circuit 4, and the control circuit 5 compares the output current signal with the sweep signal of the current sweep unit 6, and compares the difference. Is controlled so as to be zero, and a current is supplied to the superconducting magnet 1.

[Problems to be solved by the invention]

However, there is a problem that the above-described conventional AC / DC converter power supply cannot be used in a place where there is no AC power supply equipment. Further, there is a problem that a filter for eliminating the current ripple is required, and this filter is expensive and its design and manufacturing are troublesome.

These problems can be solved in principle if a battery, which is a DC power supply, can be used as it is as an excitation power supply for a superconducting magnet.However, there is no system that controls a voltage of several volts and an output current value that is a large current. It was not realized until today.

[Means for solving the problem]

The present invention has been made in view of the above-described conventional problems, and an excitation power supply device for generating a magnetic field of a superconducting magnet according to the present invention includes: a DC power supply having one terminal connected to one end of the superconducting magnet; A battery in which one terminal is connected to the other terminal of the power supply, and the other terminal is connected to the other end of the superconducting magnet.
It is characterized in that the contact area between the electrode and the electrolyte can be varied so as to be a load resistance to the DC power supply, and the output current amount of the DC power supply is varied by varying the resistance value according to the variation in the contact area. It is assumed that.

In this case, not only the primary battery and the secondary battery can be used as the DC power source, but also a DC stabilized power source can be used as in the related art without using the above-described expensive filter where the AC power source is located.

In the case of a battery using a liquid as the electrolyte, the level of the electrolyte is varied by a pump to vary the amount of output current, and the electrode is movable so that the immersion height of the electrode in the electrolyte is varied and output. The amount of current may be variable.

In addition, the output current amount can be changed by moving the electrolyte holding tank up and down to change the level of the electrolyte in the battery.

When the electrolyte is non-liquid, the output current amount may be varied so that the electrode can be inserted into and removed from the electrolyte.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, description will be made by assigning common reference numerals to parts common to the related art.

FIG. 1 is a block diagram showing one embodiment of the present invention. The battery-type excitation power supply of this embodiment is mainly a DC power supply 11,
Battery 12, holding tank 13 containing 30 wt% sulfuric acid solution H ₂ SO ₄ ,
It comprises a variable pump 14 and a quench protection circuit (not shown).

A primary battery or a secondary battery can be used as the DC power supply 11. For example, a 100 Ah battery that is usually commercially available can be used. If an AC power supply can be used, a DC stabilized power supply or the like may be used. In this case, a filter for removing the current ripple is unnecessary.

Cell 12, a PbO ₂ plates of thin and long as a positive electrode 15, the negative electrode 16 uses a PbO ₂ plates of wedge-shaped, are then dipping in a sulfuric acid solution H ₂ SO ₄ accommodated in the container 17. The positive electrode 15 is connected to the negative electrode of the DC power supply 11, and the negative electrode 16 is connected to the negative power lead 1a of the superconducting magnet 1. That is, the battery 12 is connected in series to the DC power supply 11. Therefore, if the amount of output current of the battery 12 is varied, the amount of output current as a whole can be varied, so that the battery 12 becomes a resistance to the DC power supply 11.

The type of battery used in the present invention is not particularly limited with respect to type, output voltage, output current value, and the like.
C. About 2V and output current of about 1A to 100A may be adopted.

The holding tank 13 contains the sulfuric acid solution H ₂ stored in the container 17 of the battery 12.
What is necessary is just to be able to insert and hold a material having the same property as SO _4, and there is no other required condition for the structure, material, etc. as long as the conditions are met.

The space between the container 17 of the battery 12 and the holding tank 13 is a sulfuric acid solution H ₂ SO
₄ is connected by a pipe 18 for supplying and discharging, and the level of the electrolyte can be varied by increasing or decreasing the amount of the sulfuric acid solution H ₂ SO ₄ in the container 17 by a variable amount pump 14 provided in the middle of the pipe 18 It is like that. The variable pump 14 may be any pump that can change the suction / discharge amount.
It is desirable that the relationship between the liquid level in the battery 12 and the output current value of the DC power supply 11 be substantially linear, but in the present invention, the relationship between the output current value of the battery and time can be controlled. I just need.

The variable pump 14 may use a battery-driven motor, but is not limited to this example. For example, a motor driven by a household power supply may be used. The liquid level in the battery 12 can be controlled by raising and lowering the holding tank 13 without using a pump.

FIG. 2 shows the results of experiments conducted by the present inventors. In the embodiment of FIG. 1, the output current of the DC power supply 11 was 5 A.
FIG. 9 is a diagram showing the excitation characteristics of the superconducting magnet 1 when the level of the sulfuric acid solution H ₂ SO ₄ in the holding tank 13 is adjusted so as to increase / min. The horizontal axis represents the sweep time, and the vertical axis represents the exciting current and the magnetic field strength. As shown in the figure, the output current increases linearly with the increase in the level of the sulfuric acid solution H ₂ SO ₄ to about 80 A, but an inflection point is seen at about 38 A. The generated magnetic field also exhibits similar characteristics.

This inflection point does not depend on the shapes of the positive and negative electrodes and the injection method. An experiment was conducted with the level of the sulfuric acid solution H ₂ SO ₄ rising at a constant rate. The linearity of the characteristics is maintained most, and the sulfuric acid solution H ₂ SO
_Although the level of ₄ was increased and the load was adjusted, the excitation characteristics were obtained as three straight lines having different slopes, indicating that the superconducting coil could be excited by a simple DC power supply such as a battery. In order to make the excitation characteristic of 0-5T linear, it is considered that the shape of the electrode and the injection method should be improved.

 Next, the operation of this embodiment will be described.

First, the variable amount pump 14 is driven to return the sulfuric acid solution H ₂ SO ₄ from the container 17 of the battery 12 to the holding tank 13, the level of the sulfuric acid solution H ₂ SO ₄ in the container 17 is reduced to the lowest state, The excitation of the superconducting magnet 1 is started by the output current of the power supply 11. As the excitation of the superconducting magnet 1 progresses, the variable displacement pump 14
To increase the level of the sulfuric acid solution H ₂ SO ₄ in the container 17 and increase the area of both the positive and negative electrodes 15 and 16 of the battery 12 immersed in the sulfuric acid solution H ₂ SO ₄ , thereby increasing the output current value of the battery 12. Is increased, and when a steady state is reached, the state is maintained by a superconducting switch or the like (not shown) as in the conventional case.

On the other hand, when the superconducting magnet 1 is degaussed, the level of the electrolytic solution in the battery 12 is gradually lowered by driving the variable pump 14 in a manner opposite to the above exciting operation, and the output current value to the superconducting magnet 1 is reduced. I just need.

〔The invention's effect〕

As described above, the present invention uses a DC power supply as a power supply of an excitation power supply for generating a magnetic field of a superconducting magnet, and the output current of the DC power supply is made variable by a battery acting as a variable resistor. As a result, a primary battery and a secondary battery, which could not be used in the past, can be used as an excitation power supply for a superconducting coil, and are inexpensive, simple in structure and portable, and can be used even without an AC power supply facility. There is an effect that an excitation power supply device can be provided. Also, where there is an AC power supply, a DC stabilized power supply can be used in the same manner as in the past, and even in this case, there is no noise or current ripple superimposed on the output current, so that a filter or the like is not required, and the cost is low. This has the effect of being a device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a graph showing the results of experiments conducted by the present inventors, and FIG. 3 is a block diagram showing a conventional power supply device for a superconducting magnet. is there. 1: Superconducting magnet 10: Cryostat 11: DC power supply 12: Battery 13: Tank 14: Variable pump 15: Positive electrode 16: Negative electrode 17: Container

 ────────────────────────────────────────────────── ─── Continuing from the front page (73) Patent holder 999999999 Masao Hiroi 1-9-13 Yokogi, Otsu City, Shiga Prefecture (72) Inventor Eiichi Tada 3-15-2 Komeidai, Izumi City, Osaka Prefecture (72) Inventor Muroya Masaaki 7-6-8 Higashi Tokiwadai, Toyono-cho, Toyono-gun, Osaka (72) Inventor Masao Hiroi 1-9-13, Yokogi, Otsu-shi, Shiga (72) Inventor Kohei Yamamoto 614 Washizu, Kosai-shi, Shizuoka Prefecture Fuji Electric Chemical Co., Ltd. Inside the factory (72) Inventor Masayoshi Waki 1-1-14-15 Sengen, Tsukuba-shi, Ibaraki (56) References JP-A-59-132602 (JP, A)

Claims (6)

(57) [Claims] 1. An excitation power supply for generating a magnetic field of a superconducting magnet, comprising: a DC power supply having one terminal connected to one end of the superconducting magnet; and one terminal connected to the other terminal of the DC power supply. The battery comprises a battery having the other terminal connected to the other end of the superconducting magnet, and the battery is capable of changing a contact area between an electrode and an electrolyte to be a load resistance to the DC power supply. A battery-type excitation power supply for a superconducting magnet, wherein the output current of the DC power supply is varied by varying a resistance value. 2. The battery according to claim 1, wherein the battery uses a liquid as an electrolyte, the battery includes a holding tank for containing the electrolyte, and the battery and the holding tank are connected to each other to supply and discharge the electrolyte so that the inside of the holding tank is discharged. The battery-type excitation power supply for a superconducting magnet according to claim 1, wherein the amount of output current is variable by changing the electrolyte level. 3. A battery type excitation power supply for a superconducting magnet according to claim 2, wherein a pump for supplying and discharging said electrolyte is arranged between said battery and said holding tank. 4. The battery-type excitation power supply for a superconducting magnet according to claim 2, wherein said holding tank is movable up and down, and the level of the electrolyte in said battery is variable by the vertical movement of said holding tank. 5. The battery according to claim 1, wherein the battery uses a liquid as an electrolyte, and the electrode is movable so that the height of immersion of the electrode into the electrolyte is variable to vary the amount of output current. Battery-powered excitation power supply for superconducting magnets. 6. The battery type for a superconducting magnet according to claim 1, wherein the battery uses a non-liquid electrolyte, and the output current is variable by changing the insertion height of the electrode into the non-liquid electrolyte. Excitation power supply.