JPS6043074A - Power source for nuclear fusion reactor - Google Patents

Abstract

PURPOSE:To reduce the energy loss by connecting a thyristor switch of a thyristor type DC interrupter and a thyristor switch for a feedback circuit in antiparallel, and controlling with a quench detector and a gate controller. CONSTITUTION:The second thyristor switch converter 8b to become a thyristor switch for a feedback circuit is connected in antiparallel to the first thyristor converter 8a to become a main thyristor switch. Quench detectors 10a-10n are disposed near superconductive load coils 2a-2n, and the outputs of the detectors 10a-10n are input to a gate controller 9. The controller 9 controls the first and second thyristors 8a, 8b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power source for a nuclear fusion device, and particularly to a power source for a nuclear fusion device suitable for a device having a superconducting load coil.

Figure 1 shows a conventional power supply for a nuclear fusion device, which includes a power supply 1 (la, lb, . . . in) and a superconducting load coil having protective resistors 7 (7a, 7b, . . . 7n). 2 (2a, 2b...2n), a thyristor type DC breaker 3 consisting of a main thyristor switch 3a and a forced arc extinguishing circuit 3b, a high voltage generation resistor 4, a return circuit thyristor switch 5, and a DC Circuit breaker 6 (6a, 6b...
・6n) It is structured as follows.

In FIG. 1, first, the DC circuit breaker 6 and the main thyristor switch 3a are closed, and the superconducting load coil 2 is excited by the power supply device 1. The excitation current in this case is shown by the solid arrow in FIG. 1, and the excitation current flowing through each superconducting load coil is I! +I2..., then the return circuit current IR flowing through the main risk switch 3a is expressed by the following equation.

IR-Σ II ...... (υ -1 The time when the excitation current IR of the superconducting load coil group 2a, 2b...2n reaches the set value, that is, time 11 shown in Fig. 2)
When the forced arc extinguishing circuit 3b constituting the thyristor type DC circuit breaker is operated, the main thyristor switch 3a is opened, so that the return current flows through the high voltage generation resistor 4. The current in this case is shown by the dotted arrow in FIG. When the return current flows through the high voltage generation resistor 4, the high voltage generation resistor 4 causes the superconducting load coil group 2a to be closed.

The excitation current R of the superconducting load coil groups 2a, 2b, . A plasma current Ip as shown in FIG. 2 is induced in the plasma circuit electromagnetically coupled to 2b...2n. Furthermore, in order to increase the plasma current, it is necessary to change the excitation current of the superconducting load coil 2 using the power supply 1. Through this control, in most cases, the return circuit current IR is As shown in the figure, since the polarity is reversed at time t2, the return circuit thyristor switch 5 is fired at 1=12, and the excitation current of the superconducting load coil groups 2a, 2''b...2n is routed to the return path. is formed in the direction shown by the dashed-dotted arrow in Fig. 1.In this way, in the conventional apparatus, the plasma current is induced, started up, and controlled.

However, in such a power supply for a nuclear fusion device, if the load coil is a superconducting coil, it is necessary to configure the circuit considering the quench operation as well as the normal operation. Since the power supply is used as a power source for the superconducting load coil, a low-voltage, high-current type DC power source is used.For this reason, when a quench occurs, a huge amount of magnetic energy accumulated in the superconducting load coil is used. Since it is difficult to rapidly regenerate energy into an external circuit, the DC circuit breaker 6 is opened so that the energy of the load coil is consumed by the protective resistor 7.

Therefore, in conventional devices, the total magnetic energy stored in the superconducting load coil is consumed every time a quench is performed, resulting in a large electric power loss.Furthermore, this requires a huge amount of cooling water for the protective resistor. It had problems such as requiring

It is an object of the present invention to solve the above-mentioned problems of the prior art.It is an object of the present invention to quickly absorb all the magnetic energy accumulated in the superconducting load coil into an external circuit regardless of the point at which quenching occurs, and to cool the protective resistor. The purpose is to eliminate the need for large-scale cooling equipment.

The present invention connects the thyristor switch of a thyrisk type DC breaker and the thyristor switch for the return circuit in antiparallel, and also includes a quench detector placed near a superconducting load coil, and a gate control responsive to the output of the quench detector. The purpose of the present invention is to provide a device to achieve the above object.

Hereinafter, one embodiment of the present invention will be described based on FIG.

In FIG. 3, 8a is the first thyristor converter which becomes the main thyristor switch, 8b is the second thyristor switch transformer which becomes the return circuit thyristor switch, and 9
10 (10a, 10b, . . . 40.n) is a quench detector that outputs a signal to the gate control device.

The superconducting load coils 2 (2a, 2b...2n) are excited by the power supply device 1 (la, xb...in), and the return circuit of the exciting current Iri is as shown by the solid arrow in Fig. 3. The first thyristor converter 8a is the first thyristor converter 8a. At this time, the first thyristor converter 8a is in a bypass pair state, and the second thyristor converter 8b is in a gate block state.

In this state, the superconducting load coil group 2a.

When the strong arc circuit 3b is operated when the excitation current IR of 2b...2n reaches the set value, the first thyristor converter 8a is opened, so the return current is as shown by the dotted arrow in FIG. The current flows through the high voltage generating resistor 4 as shown in FIG. Then, when the return current flows through the high voltage generation resistor 4, the high voltage generation resistor 4 causes the superconducting load coil group 2 to
The excitation currents of superconducting load coil groups 2a, 2b, .
.

A plasma current is induced in the plasma circuit electromagnetically coupled to 2b...2n. In order to further increase this plasma current, the power supply device 1 uses the excitation currents I+, I2, etc. of the superconducting load coil 2.
It is necessary to change the engineering. With this control, υ, the return circuit current IR changes over time t in most cases, as shown in Figure 2.
Since the polarity is reversed at t-12, the gate block of the second Cyrisk converter is released and the return circuit of the excitation current of the superconducting load coil groups 2a, 2b, . . . 2n is set as shown in FIG. A current path as shown by the dashed-dotted arrow line is formed.

Next, the turbulent road 9 gate control device 9 and quench detector 10 (10
a, 10b, -.Ion) will be explained. In FIG. 2, when the quench detector 10 detects the occurrence of a quench at a time point of 0≦t≦11, the gate control device 9 cancels the bypass pair of the first thyristor converter 8a and inverts the inverter. Make it work. Next, 11−≦t≦t
If a quench occurs in step 2, similarly, quench occurs in step 1.
The thyristor converter 8a is operated as an inverter, and t2≦
If a quench occurs at t, do the same again,
The second Cyrisk converter 8b is operated by an inverter.

By operating such a circuit, when a quench occurs, the first thyristor converter 8a or the second thyristor converter 8b operates together with the low-voltage current power supply 1, and the current is accumulated in the superconducting load coil 2. All of the magnetic energy generated can be quickly absorbed into the external circuit.

As stated above, according to the present invention, the first thyristor converter serving as the main thyristor switch and the second thyristor converter serving as the return circuit thyristor switch are connected in inverse parallel to each other to form a thyristor converter. By controlling the quench detector and gate control device, the energy stored in the superconducting load coil is absorbed into the external circuit, reducing energy loss and eliminating the need for large-scale cooling equipment. .

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional power supply for a fusion device, Fig. 2 is a diagram showing temporal changes in return circuit current, and Fig. 3 is a diagram of a conventional power supply for a fusion device.
FIG. 2 is a circuit diagram of a power source for a nuclear fusion device according to an embodiment. 1 (la, 1b, . . . 1n) power supply device, 2 (2a.

Claims (1)

[Claims] 1. A plurality of superconducting load coils and power supplies connected in series are connected in parallel, and the parallel connection circuit further includes a first thyristor converter serving as a main thyristor switch, and a first thyristor converter serving as a main thyristor switch. In a power supply for a nuclear fusion device in which a forced arc extinguishing circuit connected to the first thyristor converter, a second thyristor converter serving as a return circuit thyristor switch, and a high voltage generation resistor are connected in parallel, the second A quench detector is arranged in the vicinity of the superconducting load coil, and a gate control device responsive to the output of the quench detector is provided. , the first and second thyristor detectors are controlled. 2. The power source for a nuclear fusion device according to claim 1, wherein the quench detector is provided in each of the superconducting load coils.