JPS5890194A - Poloidal magmetic field generator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Misfire B) IVi relates to a poloidal magnetic field generator. In particular, it relates to a poloidal magnetic field generator that includes a normal conducting coil that generates a magnetic field that corrects the plasma to a predetermined position and shape based on the detection of the plasma position and shape, and a superconducting coil that generates a constant magnetic field. .

A poloidal magnetic field generator is used, for example, in a nuclear fusion device or the like to maintain generated plasma in a predetermined position and shape. This generally detects the position and shape of the plasma and drives the coil of the poloidal magnetic field generator based on this signal.

As a result, an appropriate magnetic field is generated, and the position and shape of the plasma are corrected to a predetermined value due to the magnetic field. In this way, feedback control of the plasma position and shape is performed on the coil for generating a voloidal magnetic field, and up to now, a normally conducting coil has been used as the coil for generating the voloidal magnetic field.

However, in recent years, in order to provide a strong magnetic field to plasma and to reduce the required power, a voloidal magnetic field generator that uses both a superconducting coil and a normally-powered coil has been proposed.

FIG. 1 shows a block diagram of such a conventional example. The conductive coil 5 is excited by the current value set by the setting device 1 and generates a constant magnetic field. The setting device 2 controls the power supply control device 2 according to the setting, and the power supply control device 2 controls the excitation power supply 3 based on this, and the superconducting coil 5 generates a magnetic field based on the setting by the excitation power supply 3. It happens. In addition, the normal conductive coil 8 is controlled via the power source control device 2 and the excitation power source 3 in the same way as the superconducting coil 5 in accordance with the command IM from the plasma position/shape control device 7, and changes according to the behavior of the plasma. Generates a magnetic field.

The behavior of plasma is determined by plasma level 1k and shape detector/fl device 9.
Based on this, the plasma position/shape control device 7 issues an appropriate control signal to correct the plasma to a predetermined position/shape.

In this way, in this conventional example, plasma is controlled by the combined magnetic field of both superconducting and normal conducting coils.

In this case, since the superconducting coils share most of the magnetic field, a strong magnetic field can be generated with a small force.

However, superconducting coils have the property that they may undergo a normal conduction transition due to factors such as current value, temperature, strain, or an external magnetic field. For this reason, a protection Ii2 circuit as shown in FIG. 2 is usually provided.

As shown in FIG. 2, when the normal conduction transition detector 13 detects the normal conduction transition of the superconducting coil 5, this protection circuit sends No. 16 to that effect to the protection control device 10. issues a demagnetization command A to the power supply control device 2, thereby controlling the excitation power supply 3 to reduce the excitation current. This is because it is generally known that the larger the coil current, the faster the rate at which the 1-conduction transition portion expands. In this way, the expansion of the normally conducting portion is prevented and recovery is waited for.

If the demagnetization does not recover even after demagnetization, and if the normally conductive portion further expands, the protection control device 10 issues a shutdown command B to shut off the circuit breaker 11.

Cut through the superconducting coil flow. At this time, superconducting coil 5
The energy stored in the discharge resistor 12 is consumed by the discharge resistor 12.

The simplest detection by the normal conduction transition detector 13 is based on a change in potential difference. It can also be detected by changes in magnetic flux or changes in helium evaporation pressure.

However, as mentioned above, when the protection device shown in Fig. 2 is applied to the voloidal magnetic field generator shown in Fig. 4, the following (1), (
2) problem remains. That is.

(1) If the superconducting coil 5 transitions to normal conductivity during the plasma control period, activates the protection device, and is demagnetized, a reliable magnetic field cannot be obtained.

(2) If the cod conduction transition progresses further and blocks the flow through the superconducting coil, a sudden change in magnetic flux will cause the normal conductive coil to
It is conceivable that an induced current is generated and the normally conducting coil 8 becomes overcurrent.

The r18 problem in (2) can be understood by referring to FIG. That is, the superconducting coil 5 and the normal conducting coil 8 are both excited and arranged so as to generate magnetic flux 16 in the same direction, so that the electromagnetic coupling between the two coils 5 and 8 is tight. In this state, the circuit breaker 11
When the superconducting coil 5 is cut off, the excitation current of the superconducting coil 5 rapidly decreases. Therefore, a current is induced in the normally conducting coil 8 in a direction that compensates for the decrease in the magnetic flux 16 due to this. By the way, the excitation current of a superconducting coil is extremely large. Therefore, it is quite possible that an overcurrent will occur in a normally conducting coil circuit that relies on induced current.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, and to minimize the influence on plasma control and the normal conduction coil even if a protective operation is performed when the conduction coil undergoes a normal conduction transition. An object of the present invention is to provide a voloidal magnetic field generating device that generates

In order to achieve this object, in the first invention according to the present application, when the superacid coil is demagnetized as a safeguard against the normal conduction transition of the superacid coil, the excitation current of the normal conduction coil is The structure is such that the magnetic field is temporarily increased to compensate for the shortage of the magnetic field.

Furthermore, in the second invention according to the present application, when the purulent retention operation leads to the superconducting coil current being cut off, the normal conducting coil excitation power source is operated by an inverter based on the cutting signal, thereby causing induction generated in the normal conducting coil. 4Yf, the configuration is such that the flow is removed.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. In this example, the present invention is applied to a voloidal magnetic field generator for controlling the position and shape of plasma in a nuclear fusion device.

This device detects the position and shape of the plasma 6 with a plasma position and shape detector 9, and based on this detection, the plasma 6 is
A normal conductive coil 8 that generates a magnetic field to correct the magnetic field to a predetermined position and shape, and a superconducting coil 5 that generates a constant magnetic field.
It is equipped with Further, when the super-fertility specialized coil 5 undergoes a normal conduction transition, this is detected by the normal conduction transition detector 13, and
A signal C is sent to the protection control device 10 in order to reduce the coil current to suppress the normal conduction transition, and as a result, the control device 10 issues demagnetization commands A to demagnetize the superconducting coil 5. In this case, the command A' is also applied to the normal conducting coil 8.
Then, the I spinning current of the normally conducting coil 8 is temporarily intensified by the command A', thereby compensating for the deficiency in the magnetic field.

Furthermore, in this device, when the normal conduction transition of the superconducting coil 5 progresses, the protection control device 10 issues a cutoff command B to cut off the coil current, but in this case, the cutoff WT signal B'
is also sent to the side of the normal conducting coil 8, the normal conducting coil excitation power source 3 is operated by an inverter, and thereby the normal conducting coil 8
This is to remove the induced current that occurs.

More specifically, the specific structure of this embodiment is as follows.

The plasma position/shape control device 7 is 7. Signal C of the plasma position/shape detector 9 that detects the actual state of the plasma 6
is input, the difference from the target value is determined, and a t-flow target value signal necessary to maintain the plasma 6 in a predetermined position and shape is output. In response to this current target value signal, the power supply control equipment 22 performs feedback control on the five excitation cage sources 32 so that the current of the 'M electric monument coil 8 reaches the target value. With such a mechanism, the plasma 6 is normally corrected by the X4 coil 8, and the shape of the plasma 6 is controlled to a positive value.

On the other hand, the ultra-high-impact coil 5 is not intended to generate a constant magnetic field, and is excited by a constant current set by the generator 1. In order to deal with this normal conduction transition of the superconducting coil 5, a stasis device is provided, which in this embodiment is a normal conduction transition detector 13. Protection control device 10
．． It is composed of an s-breaker 11 and a discharge resistor 12.

Below, when the coil 8 transfers to super 1,
The operation of this protection device will be explained. First, in the traversing state, a constant torrent is flowing through the super-heavy conducting coil 5 as shown in FIG. 4(a). This is to provide a constant magnetic field T4. A rectified current corresponding to the behavior of the plasma 6 is applied to the normal conducting coil 8 as described in (9) above, as shown in FIG. 4(b). In this way, the Chotunji coil 5. A constant current and an adjustment current are respectively passed through the regular electric coil 8, and the combined magnetic field due to both currents is as shown in FIG. 4(C).

However, when the superconducting coil 5 transitions to normal conductivity.

The matter was brought out by 13,
A code E to that effect is sent to the total protection control device 1o. Based on the information EK, the controller 10 issues a demagnetization command A to demagnetize the superconducting coil 5. This demagnetization command A is
yJ, the power control equipment 21 controls the sooJ value ridge 1M31 via the calculator 14, and the current in the superconducting coil 5 is completely extinguished.
The coil 5 is thereby demagnetized. now.

As shown in Fig. 4(d), if the current is reduced based on the demagnetization command AK and the r minute is set to Δ1s, how much current should be increased to the normally conducting coil 8 without changing the total magnetic field? Think about whether you can maintain it. Once the amount of this current to be increased is known, it would be better to correct this amount using the corrector 17r and apply it to the electric current coil 8 (lO).

The inductance of the superconducting coil 5 and the magnetic flux generated at current value 1 are respectively L#gI1gφ, and the inductance and magnetic flux generated at current value 1 of the normal conducting coil are LN, IN, respectively.
Let φ be.

Since the amount of decrease in magnetic flux when the superconducting coil 5 is demagnetized by Δ■ is, if the magnetic flux generated by the normal conducting coil is increased by Δφ8, there will be no change in the combined magnetic field generated by both coils. In this case, the current IN' flowing through the normally conducting coil
teeth.

From (11), we have . Therefore, since the current increase in the normally conducting coil 8 can be achieved by increasing the current in the coil 8 in this way, @3
As the corrector 17 in the figure, a multiplier with a coefficient of LN/L- may be provided. By operating the power control plate w, 22 via the adder 15 based on the command from the corrector 17, the plasma 6 itself is not affected in any way, and
The normal conduction transition of the superconducting coil 5 can be reliably and easily dealt with without any adverse effect on the superconducting coil 8.

Further, when the normal conduction transition progresses further and the protection control device 10 issues a disconnection command B and the circuit breaker 11 cuts off the current in the superconducting coil 5 (12), the same command signal B ' is also input to the normal conduction coil excitation power supply control device 22. Based on this signal B', the power supply control device 22 operates the normally conducting coil excitation power supply 32 as an inverter to regenerate the induced current to the alternating current side, thereby preventing excessive direct current current. That is, as can be seen from FIG. 5, by interrupting the current of the superconducting coil 5 with the circuit breaker 11, the corresponding excitation power source
The current No. 2 is discharged into the discharge resistor 12 and consumed, but at the same time, the normally conductive coil excitation power source 32 is operated by an inverter, so that the induction J? The It flow is recirculated to the AC side.

This prevents direct current overcurrent. (In the figure, numeral 16 indicates the magnetic flux. Also, numeral 4 indicates a current detector).

As described above, according to this embodiment, the superconducting coil can be protected by demagnetization without affecting plasma control. Moreover, this embodiment also has the advantage that even when the superconducting coil current is cut off, it is possible to prevent the generation of excess 'dL# due to the induced current in the normal conducting coil.

(13) As described above, the voloidal magnetic field generator of the present invention temporarily increases the excitation current of the normal conducting coil when the superconducting coil is demagnetized as a protective operation against the normal transition of the superconducting coil. This system is characterized by a structure that compensates for the lack of magnetic lift, so it does not affect the plasma itself or the normal conducting coil, so it can be used for superconducting without any negative effect on plasma control or the normal conducting coil. This has the effect that it is possible to achieve energy saving against the normal conduction transition of the coil. Furthermore, in addition to the above configuration, when the superconducting coil current is cut off as a protective operation against the normal conduction transition of the superconducting coil, the normal conducting coil wJ magnetic source is operated by an inverter according to the cutoff signal, and thereby the normal conducting coil According to the invention, which is configured to remove the induced current generated in the motor, it is possible to prevent direct current overcurrent from occurring.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional voloidal magnetic field generator.
FIG. 2 is a block diagram of a conventional 4-coil protection device. Figure 3 is a block diagram showing one embodiment (14) of the present invention, and Figures 4 (a) to (e) are diagrams each showing the operation of this embodiment. Figure 'fJ5 is a diagram explaining the action of the magnetic field generator. 5...Super-14 coil, 6...Plasma, 8...
? i [4 coils, 10...protective control device, 11...
- Breaker. Agent Patent Attorney Masami Akimoto (15) Condolences 2 Figure 0

Claims (1)

[Claims] 1. A normal conductive coil that generates a magnetic field that corrects the plasma to a predetermined position and shape based on the detection of the position and shape of the plasma, and a superconducting coil that generates a constant magnetic field. In the poloidal magnetic field generator constructed in this way, when the superconducting coil is demagnetized as a maintenance operation for the normal conduction transition of the superconducting coil, the excitation current of the normal conducting coil is temporarily increased, and thereby the shortfall in the magnetic field is A poloidal magnetic field generator characterized by having a configuration that compensates for. 2. A poloidal magnetic field consisting of a normal conductive coil that generates a magnetic field that corrects the plasma to a predetermined position and shape based on the detection of the position and shape of the plasma, and a superconducting coil that generates a negative magnetic field. In the generator, when the superconducting coil is demagnetized as a protective operation against the normal conduction transition of the superconducting coil, the excitation current of the normal coil is temporarily increased, thereby compensating for the shortage of the magnetic field. Furthermore, when the superconducting coil current is cut off as a protective operation against the normal conduction transition of the superconducting coil, the normal conducting coil excitation power source is operated by an inverter according to the cutoff signal, thereby removing the induced current generated in the normal conducting coil. A poloidal magnetic field generator characterized by having a configuration in which: