JPH04174999A - Arc power supply circuit - Google Patents

Abstract

PURPOSE:To build up an output current at a great speed by providing a bypass circuit, which consists of a series circuit comprising a resistor and a switch for bypassing, in parallel with a series circuit comprising a switch and a load, when supplying a DC output obtained from a rectification of AC to a load, that is an ion source, through a DC reactor and a semiconductor switch. CONSTITUTION:In a normal operation state, a current is supplied to an ion source 10 driving a GTO 8 during the operation period of a AC thyristor switch 2. After that, if short-circuit would occur in the ion source 10, GTO operation signal 12 provides a down-edge, that is a GTO off command, to turn off the GTO 8 so as to interrupt an output current to the ion source 10. And, in a bypass circuit operation controll circuit 17, a bypass circuit operation signal 18 is generated by the down-edge of the signal 12 to turn on a GTO 15. Consequently, the output current is built up at a great speed, when reclosing the ion source 10 after it is interrupted, by equalizing a resistor 14, connected to the GTO 15 in a circuit 13, to the resistance value of the ion source 10 as a load, when the interrupted output current is communicated into the circuit 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an internal arc power supply circuit of a source plasma generation device used in a neutral particle injection device of a nuclear fusion device.

(Prior Art) An arc power source for a neutral particle injection device is a DC power source for generating source plasma within an ion source. Arc power supplies require a large current to generate plasma, and are installed at high potentials (about 100 kV DC), so they are required to have a high-speed shutoff function when the ion source is often short-circuited.

FIG. 4 shows the main circuit configuration of a conventional arc power source. In the figure, 1 is an AC breaker, 2 is an AC thyrisk switch that controls the DC output voltage at a constant level, 3 is a step-down transformer, and 4 is a step-down transformer.
is a rectifier that converts AC voltage to DC, 5 is a smoothing capacitor, 6 is a DC reactor, 7 is a freewheeling diode, and 8 is a gate turn-off thyristor (hereinafter referred to as GTO).
), 9 is a gate circuit that drives the GTO (in the gate circuit, the on-gate is output when the reverse signal is "1", and the off-gate is output when the down edge of the operation signal is applied), 10 is an ion source, and GTO 8 is connected to the DC reactor 6. The ion sources 10 are connected in series.

In Figure 4, the number of GTOs is shown as one, or
The number of parallel GTOs is determined by (required current of the ion source 10)/(coefficient XGTOL or disconnection current). In the arc power supply circuit having such a configuration, during normal operation, when the AC thyrisk switch operation signal 11 is issued from the control panel (not shown), the AC thyrisk switch 2 changes the DC output voltage of the rectifier 4 to a preset voltage value. It is controlled to a certain extent. In this state, from the control panel (not shown)
When the TO operation signal 12 is issued, the GTO 8 is driven (turned on), a voltage is applied to the ion source 10, and a current is supplied.

Next, when a short circuit occurs in the ion source 10, it is detected by a control panel (not shown), and the GTO operation signal 12 is switched to a down edge (GTO
OFF command), the GTO 8 turns off, stops applying voltage to the ion source 10, and cuts off the current. In the ion source, a short-circuit condition often occurs in this way, but after a certain period of time (for example, several Is to several + rAS), it is required to supply arc current to the ion source again, and the number of repetitions is approximately several thousand times within a certain period of time. It is. FIG. 5 shows the operation of each part mentioned above.

(Problem to be solved by the invention) In the ion source, which is the load of the arc power source for the neutral particle injection device, when a short circuit as described above occurs, the output current of the arc power source is temporarily cut off, but the output current of the arc power source is interrupted for a certain period of time. Later, high-speed beam rise may be required. In order to start up the beam at high speed, it is necessary to start up the arc current at high speed.

However, in the above-mentioned arc power source, the value of the DC reactor 6 is large, so once the output current is cut off, it takes a long time for the output current to reach a steady state when the output current is turned on again.

There was a problem that

The purpose of the present invention was to solve the above problem, and it is possible to quickly increase the output current when supplying current to the ion source again after once cutting off the output current that was being supplied to the ion source. The purpose of the present invention is to provide an arc power supply circuit that can perform the following functions.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides an ion source that is a load by inputting an AC power source and rectifying the DC output through a DC reactor and a semiconductor switch. In the arc power supply circuit configured to supply current to the load, a bypass circuit consisting of a series circuit of a resistor and a bypass semiconductor switch is provided in parallel to the series circuit of the semiconductor switch and the load, and the resistance value of the resistor is The present invention is characterized in that the resistance value of the load is approximately the same as the resistance value of the load.

(Function) By providing the bypass circuit described above, it is possible to keep current flowing through the DC reactor at all times, and after once cutting off the output current to the ion source, when supplying current to the ion source again, the output current can be changed at high speed. It becomes possible to start up.

(Example) An embodiment of the present invention will be described below.

FIG. 1 shows an example of the main circuit configuration of an arc power source according to the present invention. Blocks having the same functions as those explained in the conventional example of FIG. Now, only the different parts will be explained. In Figure 1,
13 is a bypass circuit, which includes a resistor 14 equivalent to the load resistor, and a gate circuit 16 that drives GTO'15 and GTO15.
It is connected in parallel with the ion source 1° between the DC reactor 6 and the GTO 8. Reference numeral 17 denotes a bypass circuit operation control circuit which inputs the AC silicator switch operation signal 11 and the GTO operation signal 12 for driving the GTO 8 and generates the bypass circuit operation signal 18 for driving the GTO 15 of the bypass circuit 13. The operation of the arc power supply circuit having such a configuration will be explained.

In the normal operating state, the explanation is the same as in the conventional example shown in FIG. .

Now, if a short circuit were to occur in the ion source 1o, it would be detected by a control panel (not shown) and the GTO operation signal 12 would become a down edge (GTO off command), turning off the GTo8 and cutting off the output current that was being supplied to the ion source 10. do. or,
In the bypass circuit operation control circuit 17, the GTO operation signal 12
The bypass circuit operation signal 18 is issued at the down edge of the G
Drive (turn on) To15.

With this control, the cut off output current is commutated to the bypass circuit 13. Note that the resistor 14 is preferably selected to have a resistance value equivalent to the resistance value of the ion source 10 as a load, and the current flowing to the bypass circuit 13 is preferably limited to the same level as the current supplied to the ion source 10.

Next, when the current is to be supplied to the ion source again after a certain period of time, the GTO operation signal 12 is turned up by a control panel (not shown), the GTO 8 is driven (turned on) again, and the supply of current to the ion source 10 is started. At this time, I believe GTO driving 1
At the same time as the up edge of 2, the bypass circuit operation signal 18 is set to the down edge, GTo 15 is turned off, and the bypass circuit 1 is turned off.
If the bypass circuit operation control circuit 17 is controlled to cut off the current flowing to the ion source 3, current can be constantly passed through the DC reactor 6, and the output current supplied to the ion source 10 can be instantaneously increased. .

Incidentally, the final current cutoff of the bypass circuit 13 is performed by the down edge (off command) of the AC thyrisk switch operation signal 11.
It's easy to do.

FIG. 2 shows the operation of each part mentioned above. or,
If you want to set a time limit on the start-up time until the output current reaches a steady state, the bypass circuit operation signal 18 is set to the down edge after △ time from the up edge of the GTO operation signal 12, the GTO 15 is turned off, and the flow flows to the bypass circuit 13. This is possible if the bypass circuit operation control circuit 17 is controlled so as to cut off the current flowing therein.

However, in this case, since the output voltage is controlled to be constant by the AC thyrisk switch 2, the output current supplied to the ion source 10 and the bypass circuit 13 are controlled according to the impedance partial pressure of the ion source 10 and the resistor 14 during the time period Δ. The current flowing to is shunted.

Figure 3 shows the operation of each part mentioned above. or,
The bypass circuit 13 can be configured by changing the resistance value of the resistor 14.
By adjusting the current flowing to the output current, it is possible to similarly vary the rise time until the output current reaches a steady state.

[Effects of the Invention] As explained above, according to the present invention, after the output current being supplied to the ion source is once cut off, the output current can be raised quickly when supplying the current to the ion source again. Arc power circuits can be provided.

[Brief Description of the Drawings] Fig. 1 is a main circuit configuration diagram of an arc power source showing an embodiment of the present invention, Figs. 2 and 3 are diagrams showing the operation of each part of the embodiment, and Fig. 4 is Main circuit configuration diagram of conventional arc power supply, No. 5
The figure is a diagram showing the operation of each part of the conventional example. 1... AC breaker, 2nd A AC circuit breaker,
3... Step-down transformer, 4... Rectifier, 5... Smoothing capacitor, 6... DC reactor, 7... Free boiling diode, 8... GTo, 9... Gate circuit, DESCRIPTION OF SYMBOLS 10... Ion source, 11... AC thyrisk switch operation signal, 12... GTO operation signal, 13
...Bypass circuit, 14...Resistor, 15...GT
o, 16... Gate circuit, 17... Bypass circuit operation control circuit, 18... Bypass circuit operation signal. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] An arc power supply circuit in which an AC power source is input and a rectified DC output is supplied as a current to an ion source serving as a load via a DC reactor and a semiconductor switch, comprising: a connection between the semiconductor switch and the load; An arc power supply characterized in that a bypass circuit consisting of a series circuit of a resistor and a bypass semiconductor switch is provided in parallel to the series circuit, and the resistance value of the resistor is set to approximately the same value as the resistance value of the load. circuit.