JPS6364578A - Protective circuit for acceleration power source - Google Patents

Abstract

PURPOSE:To prevent a voltage bearing element effectively from being destroyed, by ORing a circuit comparing the input side DC voltage of a semiconductor switch with reference voltage, with a circuit detecting the current/time product of output current. CONSTITUTION:Between a semiconductor switch 50 and a reactor 60, a DC/AC device 51 is set, and the input of its current signal 500 to a control circuit 41 is provided. By the control circuit 41, this current signal is integrated, and a current/time product is detected, and when the product comes to an arbitrary current/time product or more, then semiconductor switches 311-31n are turned ON, and voltage bearing elements 321-32n are protected. When the input side DC voltage of the semiconductor switches 311-31n on the control circuit 41 exceeds reference voltage, then the semiconductor switches 311-31n are turned ON again.

Description

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

(Prior art) An acceleration power supply device for a neutral particle injection device accelerates ions in a gas that has been turned into a plasma, neutralizes the ions during the process, and injects the ions into another plasma, etc. This is a high voltage DC power supply. The Δn source, which is a load, is often short-circuited, and the accelerating power supply device is required to have a function of detecting a short-circuit and shutting it off at high speed. The main circuit of a conventional acceleration power supply device has a configuration as shown in FIG.

In FIG. 5, 11 is a thyristor switch, 12 is a voltage transformer, 13 is a rectifier, 14 is a smoothing capacitor, 1
7Af'J is an input-side DC voltage divider; 19 is an output voltage setting device; body switch [e.g. gate turn-off thyristor (GTO)] 311. 312. ...31n and
Each semiconductor switch 311. 312. ...3In
Voltage dividers, such as non-linear resistors, respectively connected in parallel] 321. 322. . . 32n, the first semiconductor switch 311. 312. ...
31n is turned on and off by the control circuit 40, thereby controlling the voltage applied to the load 18 during transient times. The steady state voltage is set by the thyristor switch 11 so that the voltage applied to the load 18 is kept constant. Also, voltage control circuit 3
A second semiconductor switch (for example, a gate turn-off thyristor (GTO)) 50 connected in series with 0 has a function of cutting off the load current. A reactor 60 connected in series with the second semiconductor switch 50 suppresses overcurrent when a short circuit occurs in the load 18, and a diode 61 connected in parallel with the reactor 60 suppresses the load current. This is to prevent the generation of overvoltage by circulating the current flowing through the reactor 60 at the time of shutoff. The control circuit 40 that controls the on/off of the voltage control circuit 30 will now be described.

FIG. 6 is a configuration diagram showing a conventional example of the control circuit 40,
In the figure, 19 is an output voltage setting device, 22 is a voltage base (((signal), signal 23△ is an input voltage signal, and 30 is a voltage control circuit, which has the same function as in FIG. 5, so its explanation will be omitted. Describing the configuration of the control circuit, 401 is a voltage error amplifier, 411.412.41n is a voltage comparator, and 421.422.42n is voltage comparator 4.
11. This is a setting device that determines each operating value of 412.41n.

To explain the operating principle in such a configuration, the voltage error amplifier 401 operates so that the voltage reference signal 22 sent from the setting device 19 and the input voltage signal 23A are equal to each other.
Automatic control and voltage comparator 411.412.

...Gives command value 401A to 41n. Voltage comparator 4
11° 412, . . . 41n, the setting device 421. 4
22. . . 42n, the operating values are given by hand-shaping in increments corresponding to the shared voltages of the voltage sharing cables.

Figure 7 ■ shows the command value 401A and the semiconductor switch 311.
, 312. . . 31n. FIG. 70 shows an example of changes in the command value 401A with respect to time t. That is, taking as an example the case where the command 1a 401A is small as the time period progresses, and therefore the applied voltage of negative vJ18 shown in FIG. 5 is kept constant, the command value 401A becomes small and the time At t1, the voltage comparator 411 reaches the operating value
A becomes even smaller and at time t2, the voltage comparator 41
When the operating value X2 of 2 is reached, the voltage comparator 412 gives an ON command to the semiconductor switch 312. At this point, the semiconductor switches 311 and 312 are in the on state and the semiconductor switches 311 and 312 are in the off state. In this way, as the command value 401Δ decreases, the semiconductor switches 311, 312. ... By giving an ON command to 31n, the applied voltage to the load 18 shown in FIG. 5 is controlled to a constant u! 1 can be done.

(Problems to be Solved by the Invention) The reference voltage signal 22 and the input voltage signal 23A are compared, and the first
Semiconductor switch 311. 312. ...31n is turned on and off, but if a problem occurs in the voltage signal 22 or the input voltage signal 23A, the first semiconductor switch 311,
312. . . 3 inches are turned off, and current continues to flow through the voltage sharing cables 321, 322, . . . 32n.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above points, and it is an object of the present invention to provide a naked-eye circuit for an accelerating power source that can prevent a voltage dividing cable from being destroyed.

[Structure of the invention]

(Means and effects for solving the problem) In order to achieve this object, the present invention provides a DC transformer between the second semiconductor switch and the axle. In addition, an ON-OFF detection circuit is provided in each first semiconductor switch, and the output current is integrated, and when the output current exceeds an arbitrary current/time product, the first semiconductor switch is turned on, and the first semiconductor switch is turned on after an arbitrary time. If the switch on confirmation signal is not issued, the thyristor switch is turned off, which prevents current from continuing to flow through the voltage divider, thereby protecting the voltage divider from destruction.

(Example) An example of the present invention is shown in FIG. 1 below. Incidentally, the same parts as in FIG. 5 are given the same reference numerals, and the description thereof will be omitted.

In FIG. 1, a DC current transformer 51 is provided between a second semiconductor switch 50 and a reactor 60, and its current signal 50
0 is input to the control circuit 41.

FIG. 2 shows a specific example of the control circuit 41. In FIG.

Components having the same or different functions as those in FIGS. 5 and 6 are designated by the same reference numerals, and a description thereof will be omitted. First semiconductor switch 311.
312. .--An ON-OFF detection circuit 90 is provided at each end of 31n. Further, an integrator 57 for integrating the output current signal 500 is installed in the control circuit 41, and 59 is a comparator;
58 is a setting device that determines the operating value of the comparator 59; 761;
762. ...76n is the first semiconductor switch 311°3
12, . . . , a time limit circuit for delaying the operation signal of 31n for an arbitrary period of time, 731. 732.・73n is an AND circuit,
711 is an LJOR circuit, 75 is an inverting circuit, 70 is an AND circuit, and 800 is an operating signal for the second semiconductor switch 50. FIG. 3 is a detailed diagram showing a specific embodiment of the ON-OFF detection circuit 90, in which 921 is a DC voltage dividing resistor, 923 is a limiting resistor, and 93 is a photodiode. Next, the operating principle of the first semiconductor switch 311 will be explained using the status display shown in FIG. In this circuit, the output current signal 500
The current/time product is detected by the integrator 57 that integrates the current/time product, and when the current/time product exceeds an arbitrary current/time product, the comparator 59 issues an ON signal to the first semiconductor switch, and the first semiconductor switch 3
11 is turned on and protects the voltage sharing cable 321.

In addition, the on signal of the first semiconductor switch 311 is set to an arbitrary value of 0. The ON confirmation signal 911 from the ON-OFF detection circuit 90 provided at both ends of the semiconductor switch 311 and the ON confirmation signal 911 (ON confirmation: OFF) are input to the AND circuit 731, and ', after the ON signal of the first half-body switch 311 has elapsed, it turns ON-OFF.
If the ON confirmation signal is not emitted from the detection circuit 90,
1) By turning off the iris switch 11, the voltage sharing cable 321. 322. ...It is possible to prevent voltage from being applied to 32n for a long time.

(Effects of the Invention) As is clear from the above, according to the present invention, the OR of the circuit that compares the input DC voltage of the first semiconductor switch with the reference voltage and the circuit that detects the current-time product of the output current can be By controlling the circuit that issues an on signal to the first semiconductor switch, and if the cylinder 1 semiconductor is not on after an arbitrary period of time, the thyristor switch is turned off, thereby eliminating voltage sharing due to malfunctions in the control signal and the semiconductor switch drive circuit, etc. It is possible to provide a protection circuit for an accelerating power source that can prevent damage to the cable.

[Brief explanation of the drawing]

FIG. 1 is an acceleration power supply circuit diagram of the present invention, FIG. 2 is a control circuit diagram of the acceleration power supply 1 of the present invention, and FIG. 3 is an ON-O
FF detection circuit diagram, Fig. 4 is a state diagram of the first semiconductor switch, Fig. 5 is a conventional 7J [1 speed power supply circuit diagram, Fig. 6 is a conventional control υV circuit diagram, Fig. 7 is It is a state diagram of the first semiconductor switch. 11...4 Noirista switch 12...Transformer 1
3... Rectifier 14... - Smoothing capacitor 17A... Input side DC voltage divider 18... Load 30
...Voltage control circuit 40...Control circuit 50.
...Second semiconductor switch 51...DC current transformer 60.
...Reactors 311-31n...First semiconductor switches 321-32
n... Voltage sharing element 35... Voltage control circuit 41... Control circuit 9
0...ON-OFF detection circuit 93...Photodiode agent Patent attorney Rule Kumi Chika Dosage Hiroshi Mitsumata Text 50θ Figure 1 Figure 3 1 φ Thick S δθθ −j1−−]−−]
111----' Figure 4 (α) 3/n 312 3// Figure 7 (b)

Claims (1)

[Claims] A plurality of first semiconductor switches connected in series to control the voltage applied to the load, each of which is provided between a DC power supply consisting of a thyristor switch, a transformer, a rectifier, and a smoothing capacitor, and a load; In an acceleration power source including a second semiconductor switch having a current cutting function connected in series to a voltage control circuit configured with a voltage sharing element connected in parallel, each of the plurality of first semiconductor switches is turned ON-- An OFF detection circuit is provided, a circuit for integrating an output current signal is added, a circuit for closing the first semiconductor switch all at once after an arbitrary current/time integration, and a drive signal for the first semiconductor switch and an ON-OFF detection circuit. A protection circuit for an accelerating power source, comprising a circuit that performs an AND operation with an ON confirmation signal of the thyristor switch and turns off the thyristor switch if the ON confirmation signal is not generated after an arbitrary period of time.