JPH0221234B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an accelerating power supply device that supplies a load voltage 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, 14 is a smoothing capacitor, and a power tube 15 connected in series with a load 18 applies or cuts off voltage to the load, and Controlled to keep the voltage constant.

The control angle of the thyristor switch 11 is
In order to keep the anode loss of the power tube 15 below a specified value, the voltage of the capacitor 14 is set to be higher than the load voltage by the voltage drop of the power tube 15. 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. A drive signal 21 is sent from the voltage control circuit 20 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 several MHz
To some extent, voltage control circuit 20, power tube drive circuit 1
If the response of 6 is selected quickly, the response of the automatic control closed loop will be approximately determined by the time constant of the load 18 (consisting of a capacitor and a resistor, not shown). 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 gradually increasing, 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 cannot be expected to have a long life. Due to the operating principle of power tubes, X-rays are generated when the voltage exceeds 10KV, so an X-ray shield with a lead plate is required.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide an accelerating power supply device that does not use a voltage 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.Up to this point, the conventional device has the same structure and the same functions as in FIG. 1. 15 is a diode, and 16 is a reactor, which has a primary winding 161 and a secondary winding 162, and the turns ratio thereof is N:1. 17 is a thyristor rectifier, 18 is a transformer, 1
9 is a setting device, 20 is a current detector, 21 is a current control circuit, 22 is a gate turn-off thyristor (hereinafter abbreviated as GTO), and 23 is a load. To explain the operation in such a configuration, first, the control angle of the thyristor switch 11 is set, and the control angle of the capacitor 14 is set.
Determine the voltage. Next, the thyristor rectifier 17 is operated to cause a current (this current is tentatively referred to as a bias current) to flow through the diode 15 via the primary winding 161 of the reactor 16. The value of the bias current 1a is determined by the current control circuit 21 and set by the setter 1.
A phase control signal 26 is sent to the thyristor rectifier 17 so that the current reference signal 24 sent from the thyristor rectifier 9 becomes equal to the current signal 25 detected by the current transformer 20, and is automatically controlled. In this state, GTO22
When ignited, a rapidly rising current whose peak value is determined by the bias current I _B and the turns ratio N of the reactor 16 can be supplied to the load 23 .

That is, before the GTO 22 is ignited, the bias current I _B flows through the path of the thyristor rectifier 17 → the primary winding 16 ₁ of the reactor 16 → the diode 15 → the thyristor rectifier 17. Next, when GTO22 is ignited, the load current I _L is larger than the bias current I _B
If the output voltage of the rectifier 13 is set so that
is reverse biased, so the load current I _L flows from the thyristor rectifier 17 to the primary winding 16 of the reactor 16 ₁
→Secondary winding 16 of reactor 16 ₂ →GTO22→
It flows through the path of the load 23. Here reactor 16
From the law of equal ampere turns, N・I _B = N・I _L +1・I _L ...(1) Equation (1) holds, and when I _L is determined from this equation (1), I _L = I _B・N/(N+1).

In this way, when GTO22 turns off, the turn-on time of GTO is less than 20μs,
It is possible to supply a load current I _L whose rise is steep and whose peak value is determined by I _B and N, and whether the load current I _L is increased or decreased thereafter depends on the output voltage of the rectifier 13.

If the load is short-circuited, the load current will change to the dotted line in the diagram.
Since the current flows as shown in (A), an increase in the load current is suppressed by the reactor 16.

GTO22 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 16
The effect of this is to limit the increase in load current to a current value that can be cut off by the GTO. G.T.O.
The turn-off time of No. 22 is less than 20 μs, which is a value that fully satisfies the turn-off time required of an acceleration power supply device. Diodes and GTOs are both semiconductors and have a semi-permanent lifespan.

As explained above, according to the present invention, it is possible to provide an accelerating power supply device having the functions of quick start-up and fast decay required for an accelerating 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, in Fig. 1, 15... Power tube, 16...
Power tube drive circuit, 17... Voltage divider, 18... Load, 19... Setting device, 20... Voltage control circuit, 1
5...Diode, 16...Reactor, 17...
...Thyristor rectifier, 18...Transformer, 19...
Setting device, 20...Current transformer, 21...Current control circuit, 22...GTO, 23...Load.

Claims (1)

[Claims] 1. A DC power supply that supplies a desired DC current to a load, a reactor in which two windings are connected in series and magnetically coupled, and a polarity provided to block a load current connected between the DC power supply terminals. a series circuit consisting of a diode, one winding of the reactor, and a load; a gate turn-off thyristor provided with a polarity in a direction that causes a load current to flow in series with the load; An acceleration power supply device comprising a bias power supply that supplies a predetermined forward bias current through the bias power supply.