JPS5930037B2 - High voltage generator for nuclear fusion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high voltage generator for a nuclear fusion device.

An example of a conventional high voltage generator for a nuclear fusion device is shown in FIG.

In the figure, an alternating current from an alternating current power source 1 is rectified by a controlled rectifier 2, and a direct current is supplied to a current transformer coil 4 via a switch 3.

A resistor 5 is connected in parallel to the current transformer coil 4. A circuit is provided between the switch 3 and the current transformer coil 4 that conducts the current flowing through the current transformer coil 4, cuts off the current while the current is flowing through the current transformer coil 4, and passes the current through the resistor 5. A main thyristor 6 is provided which is used as a breaker to commutate current to the main thyristor 6. An auxiliary thyristor 7 is connected in parallel to this main thyristor 6.
A commutation circuit consisting of a capacitor 8 and a reactor 9 is provided, and a power source 10 for charging the capacitor 8 is provided. A plasma circuit 11 is magnetically coupled to the current transformer coil 4 . A plasma stabilizing coil 12 is connected to the current transformer coil 4.
A block diode 13 is provided between the plasma stabilizing coil 12 and the plasma stabilizing coil 12 to prevent reverse current flow. The stabilizing coil 12 is connected to an AC power source 16 via a switch 14 controlled rectifier 15. Next, the operation of the device constructed in this way will be explained with reference to FIG.

In FIG. 1, the switch 3 is closed and the controlled rectifier 2 causes a current il to flow through the current transformer coil 4.

Then, as shown in FIG. 2, when the polarity of the voltage of the control rectifier 2 is reversed at t1, the main thyristor 6 is fired at the internal time. The current 12 of the control rectifier 2 is commutated to the main thyristor 6 and becomes zero at 2. Note that the voltage at this time is almost zero because it is short-circuited by the king thyristor 6.
Also, when t<t1, T. > T, is extremely small compared to the high voltage generated at T. When t>T, current 1 in current transformer coil 4
1 is flowing through the main thyristor 6 and the current in the switch 3 is zero, so the switch 3 is opened at t=T3 and the control rectifier 2 is disconnected. When the auxiliary thyristor 7 is ignited at t=T4, a commutated current 14 begins to flow through the commutating circuit consisting of the capacitor 8, the reactor 9, the main thyristor 6, and the auxiliary thyristor 7, which have been charged in advance by the power source 10.

The current 14 of the main thyristor 6 decreases to zero at t=T, and the main thyristor 6 is turned off. After this, commutation current 14 and current transformer coil current 11 flow through resistor 5.

This is indicated by I5. At t=T, the current 15 of the resistor 5 is reversed, and at t=T7, the commutation current 14 becomes zero. In this way, the current transformer coil current 14 will now flow through the resistor 5 and the terminal voltage of the current transformer coil 4 will rise with negative polarity as shown at v, magnetically coupling the current transformer coil 4 A high voltage is also induced in the plasma circuit 11, and a plasma current begins to flow. By the way, in this conventional device, between t=T5 and T6, the terminal voltage of the current transformer coil 4 is:
A voltage of opposite polarity to that used to generate plasma is generated.

Although this reverse voltage is necessary to turn off the main thyristor 6, in order to ensure sufficient turn-off conditions, the maximum value of the commutation current 14 is set at the current transformer coil current 11=I
It is necessary to have a voltage of 1:2 or more, and the maximum value of reverse electric property is 0.2 times or more of the voltage at the time of plasma generation. This voltage is quite high, and it is quite conceivable that a voltage of opposite polarity will be generated in the plasma circuit 11, and a plasma current will begin to flow in the opposite direction.

If such a current flows, it not only consumes the energy stored in the current transformer coil 11 but also has a great negative effect on the stability of the plasma, making it impossible for the fusion device to achieve its intended purpose. I end up not having it. The present invention has been made in view of the above points, and an object of the present invention is to provide a high voltage generator for the fusion device capable of stably generating plasma.

The present invention is characterized in that a rectifier circuit is provided in parallel with the current transformer coil to bypass the current from the commutator circuit after the commutator circuit is activated and the current is cut off by a circuit breaker made of a thyristor or the like. That is.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 shows an embodiment of the present invention.

In this embodiment, a thyristor 17 is connected in parallel to the current transformer coil 4 as a rectifier circuit. This thyristor 17 is not fired at t<T shown in FIG.
The current of the controlled rectifier 2 flows into the current transformer coil 4. t=T
, during the period t=T6, the thyristor 17 is fired, and the current flowing through the capacitor 8 of the commutation circuit flows through the thyristor 6.
flows through thyristor 17 after turning off. This allows the capacitor 8 to pass through the resistor 5 or current transformer coil 4.
This can prevent current from flowing. A reverse voltage can be prevented from being applied to the current transformer coil 4. FIG. 4 shows another embodiment of the invention.

In this embodiment, the thyristor 17 of the embodiment shown in FIG.
Instead, diode 18 and switch 1 are used as a rectifier circuit.
There are 9. The switch 19 is closed during the period from t=T5 to t=T6 in FIG. 2, and the current from the capacitor 8 flows through the switch 19 and the diode 18. With this configuration, it is possible to prevent a reverse voltage from being applied to the current transformer coil 4. This embodiment can be constructed at a lower cost than one using a thyristor. In both the embodiments shown in FIGS. 3 and 4, a thyristor 17 or a diode 18 is used.
The conduction time of the current is between t=T5 and T6, and the magnitude of the current is also smaller than the current 11 of the current transformer coil 4, so the capacitance of the thyristor 17 and the diode 18 may be small.

FIG. 5 shows still another embodiment of the present invention, in which a reverse conducting thyristor 20 and a switch 21 are provided in place of the main thyristor 6.

In this embodiment, the reverse conduction thyristor 20 also serves as a circuit breaker and a rectifier circuit, and by turning on the switch 21 and the reverse conduction thyristor 20, the current transformer coil 4 and the switch 21 are turned on.
A current is passed through the reverse conduction thyristor 20, the auxiliary thyristor 7 is turned on, an oscillating current is caused by the capacitor 8 and the reactor 9, and the reverse conduction thyristor 20 is turned off.
In this case, the current from capacitor 8 is reverse conducting thyristor 2
It flows through 0 and has no effect on others. By using the reverse conducting thyristor 20, it can be turned off reliably. Figure 6 shows an air-core current transformer coil 4 with an AC power source 1,
A case is shown in which excitation power sources consisting of a controlled rectifier 2 are connected in series.

The plasma stabilizing coil 12 is also connected in series with an excitation power source. In this case, since both coil currents can be controlled independently, no block diode is required. Also, there is no need for a switch to prevent high voltages from being applied to the power supply when they occur. In this case, the high voltage is applied to most of the coils, and if necessary, a controlled rectifier can be placed in a bypass pair to prevent overvoltage.
Main thyristor 6 which is air core current transformer coil current bridge and breaker
flows through. By turning on the auxiliary thyristor 7, a commutated current flows, and the main thyristor 6 is immediately cut off. Here, an overvoltage in the effective direction when the diode 18, which is a rectifier circuit, is connected or disconnected can be prevented as in other embodiments. In the above embodiments, the main thyristor 6 is provided as the ladder or disconnector, and the auxiliary thyristor 7 is provided as the control switch of the commutation circuit. can also be similarly implemented.

As explained above, according to the present invention, a rectifier is provided in parallel with the current transformer coil to allow the current from the capacitor of the commutation device to flow, so that the required voltage is generated in the current transformer coil. Accordingly, it is possible to obtain a high voltage generator for a nuclear fusion device that can prevent the generation of a voltage of opposite polarity immediately before generating a stable plasma.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a high voltage generator for a nuclear fusion device showing one conventional example, Fig. 2 is an operation waveform diagram of Fig. 1, and Figs. 3 to 6 show different embodiments of the present invention. FIG. 2 is a circuit diagram of a high voltage generator of the nuclear fusion device shown in FIG. 4...Current transformer coil, 5...Resistance, 6
...Main thyristor, 7...Auxiliary thyristor, 8...Capacitor, 9...Reactor, 11...Plasma circuit, 12...・・・
...Plasma stabilization coil, 17...thyristor, 18...diode, 19...
・Switch, 20... Reverse conduction thyristor, 21
...Switch.

Claims (1)

[Claims] 1 A current transformer coil for plasma generation connected to a DC power supply, a resistor connected in parallel to the current transformer coil, and a resistor connected in parallel to the current transformer coil, and a current flowing through the current transformer coil is energized. A breaker is connected in parallel to the breaker, which cuts off the current when current is flowing through the current transformer coil, and a breaker is connected in parallel to the breaker. a commutation circuit that supplies a current in the opposite direction to the current flowing through the disconnector;
In the device provided with a plasma circuit magnetically coupled to the current transformer coil, in parallel with the current transformer coil, a current from the commutation circuit after the current is cut off by the shunt breaker. A high voltage generator for a nuclear fusion device, characterized in that it is provided with a rectifier circuit that bypasses the.