JPH0254035B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a power supply device for a nuclear fusion device, and particularly to a power supply device for a nuclear fusion device that provides good protection when plasma current abnormally decreases or disappears during operation. The present invention relates to a power supply device for a nuclear fusion device.

(Prior Art) Conventionally, as a power supply device for a nuclear fusion device, there is one having a circuit configuration as shown in FIG. 2, for example.

In FIG. 2, 1 is a plasma circuit that generates plasma to cause nuclear fusion, and is represented by an inductance 2 and a resistance 3. 4 is a current transformer coil magnetically coupled to the plasma circuit 1 to generate plasma in the plasma circuit 1; 5 is a resistor connected in parallel with the current transformer coil 4; 6 is a resistor 5; Diodes connected in parallel, 7 a direct current or disconnector connected in series with the diode 6, 8 a current transformer connected to both ends of the current transformer coil 4 to supply direct current to the current transformer coil 4. This is a thyristor conversion device for a coil. Also, 9 and 10
is a switch for switching the connection polarity of the thyristor conversion device 8. On the other hand, 11 is a position/shape control coil 12 which is magnetically coupled to the plasma circuit 1 and controls the position or shape of the plasma.
is a thyristor conversion device for a position/shape control coil that is connected to both ends of the position/shape control coil 11 and supplies direct current to the position/shape control coil 11.

Next, the operation of the power supply device of such a nuclear fusion device will be explained using FIG.

In FIG. 3, A indicates the current of the plasma circuit 1, B indicates the current of the current transformer coil 4, C indicates the current of the position/shape control coil 11, and D indicates the thyristor conversion device 8 of the power supply for the current transformer coil 4. , E represents the direct current or current of the disconnector 7, F represents the current of the resistor 5, and G and J represent the operations of the switches 9 and 10, respectively.

First, with the switch 9 closed, the current transformer coil 4 is excited by the thyristor converter 8 at time _t1 . After the current reaches a predetermined value, if the thyristor conversion device 8 is put into reverse conversion operation at time _t2 , the diode 6 is energized and the current in the thyristor conversion device 8 is transferred to the direct current or the disconnector 7 and flows. It becomes like this. Thereafter, the switch 9 is opened to disconnect the thyristor conversion device 8 from the current transformer coil 4. Next, at time _t3 , when the direct current or the breaker 7 is opened to cut off the current, the current in the current transformer coil 4 flows through the resistor 5 and rapidly decreases.
High voltage is generated between the coil terminals. This voltage generates plasma in the plasma circuit 1 and increases the plasma current. Next, at time _t4 , the switch 10 is closed, the thyristor converter 8 is connected to the opposite polarity, the current in the current transformer coil 4 is changed as shown in FIG. 3B, and the plasma current is shown in A. It is kept constant until time t ₅ , and then slowly decreased and stopped. Here, in order to keep the plasma current constant, the current in the current transformer coil 4 must be changed as shown in Figure 3B, because it compensates for the voltage drop due to the resistance 3 of the plasma itself. This is because it is indispensable.

However, in such an operation, the plasma current often suddenly decreases or disappears due to an abnormality in the plasma itself. Therefore, a large abnormal voltage is generated at each coil terminal due to mutual induction. This point will be explained below using the circuit of the current transformer coil 4 as an example.

First, the following equation holds true for the current transformer coil circuit.

L _f・di _f /dt＋R _f i _f +M _pf・di _p /dt +ΣM _fj・di _f /dt=e _f ...(1) where, i _p :Plasma current i _f :Current transformer coil current i _j : Current in other coils L _f : Self-inductance of the current transformer coil R _f : Resistance of the current transformer coil M _pf : Mutual inductance between the plasma and current transformer coil M _fj : Mutual inductance between the current transformer coil and other coils Inductance e _f : Voltage of current transformer coil Generally, the influence of the fourth term on the left side of equation (1) is relatively small and is therefore ignored. Now, as shown in Fig. 4A, if the plasma current rapidly disappears at t = _t6 , the current in the current transformer coil 4 is di _f /dt = (1/L _f ) {-M _pf・di _p /dt −R _f i _f +e _f } …(2) Changes. On the right side, current transformer coil 4
The voltage e _f is the forward output voltage of the thyristor conversion device 8, and R _f i _f is also small, so di _f /dt≒−(M _pf /L _f )・(di _p /dt)... (3) becomes. Since di _p /dt is negative, the absolute value of the current i _f in the current transformer coil 4 decreases from the negative value at t=t ₆ to zero. This situation is shown by the solid line in FIG. Thereafter, since the thyristor conversion device 8 prevents the current from passing through the current transformer coil 4 in the positive direction, a voltage of magnitude M _pf · _dip /dt is generated across the current transformer coil 4 .

(Problem to be solved by the invention) This voltage can reach tens of thousands of volts,
There is a risk that the thyristor conversion device 8 and the current transformer coil 4 will be damaged.

Although the case in the circuit of the current transformer coil 4 has been described above, the same problem occurs in the circuit of the position/shape control coil 11 as well.

An object of the present invention is to prevent damage to thyristor conversion devices, current transformer coils, and position/shape control coils by eliminating generation of abnormal voltage even when plasma current abnormally decreases or disappears. The object of the present invention is to provide an extremely reliable power supply device for a nuclear fusion device.

[Structure of the Invention] (Means and Effects for Solving the Problems) To achieve the above object, the present invention provides a current transformer coil magnetically coupled to a plasma circuit that generates plasma to generate nuclear fusion. , a thyristor converter for the current transformer coil connected to both ends of the current transformer coil, a resistor connected in parallel with the current transformer coil, a diode connected in parallel with the resistor, and a thyristor converter device connected in series with the diode. For switching the connection polarity of a thyristor converter for a current transformer coil connected between a DC or disconnector connected to the diodes, a series circuit of a diode, a DC or disconnector, and a thyristor converter for the current transformer coil. switch, a position/shape control coil magnetically coupled to the plasma circuit, and a position/shape control coil magnetically coupled to the plasma circuit.
In a power supply device for a nuclear fusion device equipped with a thyristor converter for position/shape control coil connected to both ends of a shape control coil, a thyristor and a thyristor are connected in parallel with both the current transformer coil and the position/shape control coil. , a self-ignition type gate circuit that detects the voltage between the anode and cathode of the thyristor and generates a gate pulse to ignite the thyristor when the voltage becomes larger than a predetermined value. A firing type thyristor switch is provided, and a short circuit switch is provided in parallel with the self firing type thyristor switch, which is closed when the self firing type thyristor switch is fired.

There is.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing an example of the configuration of a power supply device for a nuclear fusion device according to the present invention. In FIG. 1, each element numbered 1 to 12 is the same as the element shown in FIG. 2, so a description thereof will be omitted, and only the different parts will be described here.

That is, in FIG. 1, a self-ignition type thyristor switch 13 is provided in parallel with the current transformer coil 4, and a self-ignition type thyristor switch 16 is provided in parallel with the position/shape control coil 11.
Here, the self-ignition type thyristor switch 13 is
A self-ignition type that detects the voltage between the thyristor 14 and the anode and cathode of the thyristor 14 and generates a gate pulse to ignite the thyristor 14 when the voltage becomes larger than a predetermined value. It consists of a gate circuit 15. Furthermore, the self-ignition type thyristor switch 16 also includes the thyristor 1.
7, and a self-ignition gate that detects the voltage between the anode and cathode of the thyristor 17 and generates a gate pulse to ignite the thyristor 17 when the voltage becomes larger than a predetermined value. circuit 18
It consists of.

Further, a short-circuit switch 20 is provided in parallel with the self-ignition type thyristor switch 13, and a short-circuit switch 21 is provided in parallel with the self-ignition type thyristor switch 16. Here, the short circuit switch 20
and 21 indicate the detection of the ignition of the self-ignition thyristor switches 13 and 16, respectively (for example, a drop in the voltage between the anode and cathode of the thyristors 14 and 17, or the current flow of the self-ignition thyristor switches 13 and 16). The circuit is closed when the current is detected.

Next, the operation of this embodiment will be explained using FIG. 4, taking as an example the circuit of the current transformer coil 4 in the power supply device of the nuclear fusion device configured as described above.
Note that the operation during normal operation is the same as that shown in FIG. 2 described above, so the explanation thereof will be omitted here.

Now, when the plasma current suddenly decreases or disappears, the negative absolute value of the current in the current transformer coil 4 decreases, and the current is intermittent, as described above. At this time, the overvoltage generated in the current transformer coil 4 is in the forward direction with respect to the thyristor 14, so the self-starting gate circuit 15 detects this voltage and, if it exceeds a predetermined overvoltage level, gates the current transformer coil 4. By generating a pulse and igniting the thyristor 14, both ends of the current transformer coil 4 are shorted, and it is possible to prevent a high voltage from being generated between the coil terminals. At this time, the current transformer coil 4 and the thyristor 14
A current flows as shown by the dotted line in FIG.

The same applies to the function of the self-starting thyristor switch 16 in the circuit of the position/shape control coil 11. The current flowing through the position/shape control coil 11 at this time is shown in FIG.

In either case, the energy generated when the plasma current suddenly decreases or disappears is absorbed by flowing current through the circuit, thereby preventing the generation of overvoltage.

On the other hand, by passing a large current through the self-starting thyristor switches 13 and 16 for a long period of time, the capacity of the thyristor switches becomes large, which may pose a problem. In this regard, in the case of this embodiment, as shown in FIG.
0 and 21 respectively, when the self-ignition type thyristor switches 13 and 16 are detected to be ignited, the short-circuit switches 20 and 21 are closed, and the current is transferred to the thyristors 14 and 17.
Since the energization time of the thyristors 14 and 17 can be shortened by moving the thyristors 14 and 17 to the short-circuit switches 20 and 21, respectively, the capacity of the thyristor switch does not become large.

As described above, in the power supply device of the fusion device according to this embodiment, even when the plasma current abnormally decreases or disappears, no abnormal voltage is generated in each coil, and the thyristor converters 8 and 12 and the converter It becomes possible to obtain a power supply device for a nuclear fusion device that is free from problems such as damage to the fluid coil 4 and the position/shape control coil 11. Furthermore, by setting the ignition levels of the self-ignition thyristor switches 13 and 16 in appropriate coordination with the breakdown voltage level of the equipment, even if there is a decrease in plasma current, it is only temporary. When overvoltage does not occur, for example, there is no need to stop the operation of the power supply device, and it is possible to improve the operating efficiency of the entire device. Furthermore, the thyristor converters 8 and 12 and the current transformer coil 4 are protected against overvoltage caused by causes other than abnormal reduction or disappearance of plasma current, such as when no plasma current is generated.
And it becomes possible to reliably protect the position/shape control coil 11. Furthermore, since the energizing time of the self-ignition type thyristor switches 13 and 16 can be shortened, the capacity of the thyristor switches does not become large.

[Effects of the Invention] As explained above, according to the present invention, even when plasma current abnormally decreases or disappears, generation of abnormal voltage can be eliminated and the thyristor converter, current transformer coil, and position/shape control coil can be improved. It is possible to provide an extremely reliable power supply device for a fusion device that can reliably prevent damage to the fusion device.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a power supply device for a fusion device according to the present invention, FIG. 2 is a circuit diagram showing an example of a conventional power supply device for a fusion device, and FIG.
FIG. 4 is a curve diagram for explaining the operation of the power supply device in the figure, and FIG. 4 is a curve diagram for explaining the circuit current when the plasma current abnormally disappears. 1...Plasma circuit, 4...Current transformer coil, 5
...Resistor, 6...Diode, 7...DC or disconnector, 8,12...Thyristor conversion device, 9,1
0... Switch, 11... Position/shape control coil, 13, 16... Self-starting thyristor switch, 14, 17... Thyristor, 15, 18...
Self-igniting gate circuit, 20, 21...Short circuit switch.

Claims (1)

[Scope of Claims] 1. A current transformer coil magnetically coupled to a plasma circuit that generates plasma to produce nuclear fusion;
a thyristor conversion device for a current transformer coil connected to both ends of the current transformer coil; a resistor connected in parallel with the current transformer coil; a diode connected in parallel with the resistor; and a thyristor conversion device for the current transformer coil connected between the series circuit of the diode and the DC current or disconnector, and the thyristor conversion device for the current transformer coil. a switch for switching connection polarity, a position/shape control coil magnetically coupled to the plasma circuit, and a position/shape control coil magnetically coupled to the plasma circuit;
In a power supply device for a nuclear fusion device comprising a thyristor conversion device for a position/shape control coil connected to both ends of a shape control coil, a thyristor is connected in parallel to both the current transformer coil and the position/shape control coil. and a self-ignition type gate circuit that detects a voltage between an anode and a cathode of the thyristor and generates a gate pulse to ignite the thyristor when the voltage becomes larger than a predetermined value. A nuclear fusion device characterized in that a self-ignition thyristor switch is provided, and a short-circuit switch that closes when the self-ignition thyristor switch is ignited is provided in parallel with the self-ignition thyristor switch. Device power supply.