JPH0133040B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an accelerating power supply device that supplies a load current with a steep rise.

The purpose of the acceleration power supply is to apply a high DC voltage to the acceleration electrode to accelerate ions, and a fast rise is required. Furthermore, the accelerating electrodes are often short-circuited, and it is required to detect and quickly break the short-circuit.

The main circuit of a conventional acceleration power supply device has a configuration as shown in FIG. In FIG. 1, 11 is a thyristor switch, 12 is a transformer, 13 is a rectifier, and 14 is a smoothing capacitor. A power tube 15 connected in series to a load 18 applies or cuts off voltage to the load, and Controlled to keep the load voltage constant. The control angle of the thyristor switch 11 is set so that the voltage of the capacitor 14 is higher than the load voltage by the voltage drop of the power tube 15 in order to keep the anode loss of the power tube 15 below a specified value. Control of the load voltage is performed as follows. The voltage control circuit 20 automatically controls the voltage reference signal 22 sent from the setting device 19 and the output voltage signal 23 detected by the voltage divider 17 to become equal. From the voltage control circuit 20, drive signal 2
1 is sent to the power tube drive circuit 16, and the grid voltage of the power tube 15 is controlled, thereby controlling the output voltage to be constant. The frequency response of the power tube 15 is on the order of several MHz, and the response of the voltage control circuit 20 and the power tube drive circuit 16 can be selected quickly. The value is approximately determined by the time constant of 18. An example of the rating of an accelerating power supply used in a neutral particle injection device for heating plasma is that the output voltage is 100KV, the output current is 100A, and the rise time is about 100μs, which can be achieved using the conventional method shown in Figure 1. level. However, in recent years, the voltage and current ratings of accelerating power sources have been increasing gradually, and it has become necessary to connect power tubes in series or in parallel, but the conventional system shown in FIG. 1 has the following drawbacks.

Power pipes with such high ratings have a very short lifespan, less than 3000 hours. Due to the operating principle of power tubes, when the voltage exceeds 10KV, X-rays that are harmful to the human body are generated, so an X-ray shield using a lead plate is required.

An object of the present invention is to eliminate the above-mentioned drawbacks, provide an acceleration power supply device that does not use a power tube, and has a completely different operating principle.

The present invention will be described below with reference to an embodiment shown in FIG. In FIG. 2, 11 is a thyristor switch, 12 is a transformer, 13 is a rectifier, and 14 is a smoothing capacitor, which up to this point have the same configuration and functions as the conventional system shown in FIG. 1. 24 is a diode, 25 is a reactor, 26 is a thyristor rectifier, 27 is a transformer, 28 is a setting device, 29 is a current detector, 30 is a current control circuit, 31 is a gate turn-off thyristor (hereinafter abbreviated as GTO), 32 is a load It is. To explain the operation in such a configuration, first, the control angle of the thyristor switch 11 is set and the voltage of the capacitor 14 is determined. Next, the thyristor rectifier 26 is operated to cause a current (this current is tentatively referred to as a bias current) to flow through the diode 24 via the reactor 25. The value of the bias current is determined by the current control circuit 30 based on the current reference signal 33 sent from the setting device 28 and the current transformer 29.
A phase control signal 35 is sent to the thyristor rectifier 26 so that the current signal 34 detected in the thyristor rectifier 26 is automatically controlled. In this state, when the GTO 31 is ignited, current is supplied to the load 32. G.T.O.
The turn-on time of No. 31 is 20 μs, and a sufficiently fast rise can be obtained.

When the load is short-circuited and the load current exceeds the bias current, the diode 24 is turned off and the load current flows as shown by the dotted line A in the figure, so the increase in the load current is caused by the reactor 25. suppressed by

GTO31 is a switching element with self-extinguishing ability, and by sending a negative signal to the gate,
The anode current can be cut off quickly. However, there is a current value that can be cut off, and the reactor 25
The effect of this is to limit the increase in load current to a current value below which the GTO 31 can be cut off.
The turn-off time of GTO31 is less than 20μs,
This value sufficiently satisfies the acceleration time required for the acceleration power supply device. Diodes and GTOs are both semiconductors and have a semi-permanent lifespan.

As described above, according to the present invention, it is possible to provide an acceleration power supply device that has the functions of quick start-up and fast decay required for an acceleration power supply device without using a power tube.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a conventional acceleration power supply device, and FIG. 2 is a configuration diagram of an acceleration power supply device showing an embodiment of the present invention. 11... Thyristor switch, 12... Transformer, 13... Rectifier, 14... Smoothing capacitor, 24... Diode, 25... Reactor,
26...Thyristor rectifier, 27...Transformer, 2
8... Setting device, 29... Current transformer, 30... Current control circuit, 31... GTO, 32... Load.

Claims (1)

[Claims] 1. A DC power supply, a gate turn-off thyristor that opens and closes the load current supplied from the DC power supply, a diode connected in series with this gate turn-off thyristor with a polarity that blocks the load current, and a bias current flowing through this diode. An accelerating power supply device consisting of a thyristor rectifier connected in parallel via a reactor, and a current control circuit that controls the output current of the thyristor rectifier to a desired value.