JPS5935561A - Method and device for controlling self-extinguishing type thyristor - Google Patents

Abstract

PURPOSE:To effectively reduce the heat generation of a snubber circuit by effectively transferring the charge of a condenser which is consumed in a snubber resistance section at the turning OFF time to the other. CONSTITUTION:A thyristor 19 is conducted by an ON signal at the turning ON time to charge a condenser 17, but when an SI (static induction) thyristor 1 becomes conductive state, the forward voltage of the thyristor 19 becomes zero, with the result that the thyristor 19 can be extinguished. A thyristor 20 is conducted by an OFF signal at the turning OFF time to flow a reverse current to the gate of the thyristor 1, which is thus turned OFF to flow a charging current to the condensers 14, 15. When the charge of the condenser 15 is discharged, a reverse bias is applied to the thyristor 20, resulting in the extinguishment of the thyristor 20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method and apparatus for controlling a self-extinguishing thyristor such as a gate turn-off thyristor or a conductive thyristor, particularly a special turn-off function.

Conventionally, gate turn-off thyristors (hereinafter referred to as GTO thyristors) have been commonly used as self-extinguishing thyristors, and electrostatic induction thyristors (hereinafter referred to as SI thyristors) are known as a new type.

This 8I thyristor is the cathode of the current-carrying element, similar to the GTO Thyrisk.

The device can be turned off by applying a reverse bias voltage between the gates. Regarding turn-on, there are two types: a normally-off type that requires applying a forward bias between the gate and cathode like the GTO thyristor, and a normally-on type that turns on simply by removing the reverse bias between the gate and cathode. There are types. All of them are characterized by extremely fast switching times, and combined with the fact that they can easily be made to withstand high voltages, they are considered very promising as switching elements for high frequency and high power applications.

Next, a typical example of a DC switch circuit using a GTO thyristor or an 8I thyristor is shown in FIG.

Figure 1 shows an example of the configuration of a DC switch circuit using normally-off type SI thyristors.
．． 12 is a capacitor, 6 is a resistor, 7°13 is a diode, 8 is a turn-on switch, 9 is a turn-off switch, and 10.11 is a power supply.

In other words, when operating the circuit configuration using the 8I thyristor as described above, it is performed as follows.

Here, for ease of understanding, time charts showing the state of waveforms of each part of the circuit shown in FIG. 1 are shown in FIG. 2(a),
Shown in (b). In addition, T! T2 is the time when the turn-on switch 8 is turned on, and T2 is the time when the turn-off switch 9 is turned on.

Now, in FIG. 1, with the turn-on switch 8 turned off, the turn-off switch 9 is closed, and the voltage E2 of the power supply 11 is applied between the cathode and gate of the 8I thyristor 1 through the diode 13. When closed, the voltage Es of the main power supply 2 is applied between the anode and cathode of the 8I thyristor 1 through the resistor 3, so that the capacitor 5 is charged through the diode 7 and becomes equal to the voltage of the main power supply 2.

Here, when turning on the S ethyristor 1, the turn-off switch 9f3 is turned off and the turn-on switch 8 is turned on. Then, a closed circuit is formed in the path of power supply 10 → turn-on switch 8 → capacitor 12 → SI thyristor 1 (gate electrode to cathode electrode) → power supply 10, and the capacitor 12 is charged.

The current can flow and cause the SI thyristor 1 to conduct. At this time, the capacitor 12 is charged to the voltage B of the power supply 10 with the polarity shown. When the SI thyristor 1 is turned on, the charge stored in the capacitor 5 is discharged via the resistor 6, and the energy is consumed by the resistor 6 and converted into heat.

Further, in order to turn on the SI thyristor 1 which is currently energized, the turn-on switch 8 is turned off and the turn-off switch 9 is turned on. At this time, the gate of the 8I thyristor 1 is connected to the power supply 11 → 8I thyristor 1 (cando electrode ~
The voltage E2 of the power supply 11 and the voltage Vc of the capacitor 12 are added together and applied along the path of (gate electrode) → capacitor 12 → turn-off switch 9 → power supply 11, and excess carriers inside the S ethyristor 1 cause gate reverse current. As a result, the SI thyristor 1 is quickly turned off as it is swept out from the gate electrode. As a result, the capacitor 5 is again connected to the voltage E of the main power supply 2.
It is charged at st and keeps the 8I thyristor 1 in a non-conductive circuit state.

In this way, the self-extinguishing thyristor is useful because it can control the gate current and turn on and off the main current IT, but the method of circuit configuration of the gate circuit section is In particular, there was a drawback that the gate current was drawn out far apart at turn-off. This is the main current I for a certain value
In order to cut off T, a certain amount or more is required, for example, approximately (Ir15) for a GTO thyristor.

This is because in SI psionics, it is necessary to flow a gate reverse current larger than that, and fast start-up characteristics are required to reduce the effects of hot spots generated inside the device. This problem becomes more difficult to solve as the capacity of devices increases. There is also a problem with the discharge of the capacitor 5 that occurs when the capacitor 5 is turned on, and as mentioned above, the energy stored in the capacitor 5 is dissipated as thermal energy by the resistor 6. As the frequency increases, it becomes necessary to increase the capacitance of the resistor.This invention was made in order to solve the above-mentioned problems, and effectively transfers the charge accumulated in the capacitor to another, thereby reducing excess charge at turn-off. It is an object of the present invention to provide a control method and device that are effective for use in sweeping out carriers. The present invention will be explained below based on the drawings.

3 and 4 are explanatory diagrams of the operating principle shown to explain the technical idea of the present invention and time charts showing the states of waveforms of each part.
is a diode and 18 resistors. In the figure, the same reference numerals as in FIG. 1 indicate parts having the same functions. Here, the temporal transition of the waveform due to turning on of the turn-on switch 8 and the turn-off switch 9 is shown based on the enlarged diagram of FIG. 4.

That is, in the circuit configuration shown in FIG. 3(a),
First, turn-on switch 8 and turn-off switch 9
When the voltage of the main power supply 2 is applied between the anode and the cathode of the thyristor 1 by turning off the switch 4 and turning on the switch 4, the capacitor 14 is connected to the diode 16.
is charged to a voltage Es through the voltage Es. Next, when the turn-on switch 8 is turned on, the capacitor 17 is charged via the resistor 18, the voltage of the capacitor 17 increases, and the voltage between the gate and cathode of the 8I thyristor 1 is α
The SI thyristor 1 can be made conductive at the time when the SI thyristor 1 is positively biased. This forms a closed circuit of capacitor 14 -> SI thyristor 1 (7 node electrode - cando electrode) -> capacitor 15 -> capacitor 14, and the capacitor 14 is discharged! A current is passed through it. This is shown in Figure 3 (b
). Therefore, the capacitor 15 is charged with the polarity shown, and furthermore, the voltage vscs of the capacitor J4 after discharge is equal to the voltage VSC2 of the capacitor 15 υ Its value is expressed by equation (1). . However, C1*C2 is the capacitance of capacitor 14.15 (μF
).

The waveforms of each part having such a relationship are shown as shown in FIG. 4(a).

Further, when the turn-on switch 8 is turned off and the turn-off switch 9 is turned on, the capacitor 15 → 8I thyristor 1 (cathode electrode to gate electrode) → turn-off switch 9 as shown by the dashed line in FIG. 3(C). → A closed circuit of the capacitor 15 is formed, a reverse current flows to the gate of the SI thyristor 1, and the 81-day thyristor 1 starts to turn off. At this time, the excess carriers in the SI thyristor 1 are swept out, and the reverse voltage between the cathode and the gate of the SI thyristor 1 is restored.
Connect capacitor 1 with the polarity shown in the diagram as indicated by the two-dot chain line.
The battery will be charged until the voltage reaches a voltage equal to 5. Then, as the SI thyristor 1 turns off and the voltage between the anode and cathode begins to recover, the main power supply 2 → resistor 3 → switch 4 → capacitor 14 as shown in FIG. 3(d).
Since a current flows in the path of → capacitor 15 → main power supply 2, if the turn-off switch 9 is turned off at this time, the capacitor 14 will be charged to the polarity shown, and the charge of the polarity shown will remain in the capacitor 17. The gate and cathode of the thyristor 1 are reverse biased. Further, when the capacitor 15 is discharged and its charging voltage is reversed, the voltage VSCI of the capacitor 14 due to conduction to the diode 16 is charged to the voltage B8 and returns to its original state. The waveforms of each part of these relationships are shown in Figure 4 (b
).

Therefore, in the technology based on this technical concept, the charge stored in the snubber capacitor (1) at turn-off is used to sweep out excess carriers of the element at the next turn-off, and compared to the conventional method, the charge stored in the snubber capacitor (1) is used to sweep out excess carriers of the element at turn-off. In addition, the power generated by the snubber circuit can be effectively reduced by effectively transferring the capacitor charge that was consumed in the snubber resistor at turn-off. The present invention will be described in detail with reference to specific embodiment drawings.

FIG. 5 is a circuit diagram showing an embodiment of the present invention similar to FIG. 3(a), and 19.20 is a conventional thyristor. In the figure, the same reference numerals as in FIG. 3(a) indicate the same components. That is, in the circuit shown in FIG. 5, the turn-on switch 8 and the turn-off switch 9 of the circuit configuration I) in FIG. 3 are composed of thyristors 19 and 20), and have the following functions.

In FIG. 5, when turned on, the thyristor 19 is made conductive by an on signal (not shown), and the thyristor 19 can be turned off for condensation. Also, at turn-off, the thyristor 20 is turned on by an off signal (not shown) and a reverse current flows to the gate of the 8I thyristor 1, but when the SI thyristor 1 is turned off, a charging current flows to the capacitors 14 and 15, and the capacitor 15 is turned on. When the charge is discharged, a reverse bias is applied to the thyristor 20, so that it can be turned off.

The sixth factor and FIG. 7 are circuit diagrams showing other embodiments of the present invention similar to the device shown in FIG. 1, in which 21 is a conventional thyristor and 22 is a gate control circuit. In other words, such
This is a specific example in which a commonly used gate control circuit is combined with the technical idea explained in the figure. In FIG. The ignition circuit portion of the thyristor 21 is shown, and in order to facilitate understanding of the gate control circuit portion 22, the same parts as shown in FIG. 1 are given the same reference numerals. The operation of the ignition circuit portion 22c as described above is well known and will not be described in detail.

It is clear that the one shown in Kayo 5 has the function of turning on the turn-off switch 9 to apply a reverse voltage between the gate and cathode of the SI thyristor 1, and simultaneously firing the thyristor 21. In addition, the gate control circuit section 22 may be of any type as long as it has a function of turning on the s-esthyristor 1 and a function of applying a reverse bias to the gate during the turn-off period, and sweeps out excess carriers at the time of turn-off, which requires a large current. capacitor 15
Since it is performed with a discharge current of , it is obvious that a simple device with low electric power is sufficient.

In addition to the circuit configuration of this embodiment, the discharge of the snubber capacitor that flows at the moment when the 8I thyristor is turned on.
In order to limit the current, a configuration as shown in FIG. 8 or FIG. 9 may be used.

That is, FIGS. 8 and 9 are partial connection diagrams showing modifications of the capacitor circuit shown in FIGS. 5 and 6, where 2:11.23' is a resistor, 24 is a diode, and 25
．． It is a 25' beam Akdol. In the figure, the same reference numerals as in FIGS. 5 and 6 indicate parts having the same functions. In this way, for example, as shown in FIGS. 8(a) and 8(b), a current suppressing circuit is added, such as connecting a resistor 23 in series with the capacitor 14 or a parallel circuit consisting of an axle 25 and a diode 24. or added to the capacitor 15 side. Although the embodiment drawings show a diode 16 added in parallel to the capacitor 15, it is clear that even if the diode 16 is removed, the present invention can still be effective without impairing the function. I would like to add that the addition of this will further improve the effect.

As described above, according to the present invention, it is possible to provide an exceptional control method and apparatus, particularly for supplying gate power from the main circuit during turn-off.

[Brief explanation of the drawing]

Figures 1 and 2 are circuit diagrams showing configuration examples of DC and switch circuits that employ SI thyristors, time charts showing the 1/' state of waveforms at various parts, and Figures 3 and 4 are diagrams showing the technology of the present invention. FIG. 5 is a circuit diagram showing an embodiment of the present invention; FIG. FIG. 7 is a circuit diagram showing another embodiment of the present invention, a circuit diagram showing a gate control circuit section, and FIGS. 8 and 9 are partial connection diagrams showing modifications of the capacitor circuit section.・・・・・・Static induction psirisk (SI psisk), 2・・・・・・・・・Main power supply, 5, 12, 14
, 15.17... Capacitor, 7, 13
．． 16...Song...Diode, 8...Song...Turn-on switch, 9...Turn-off switch, 19.20,21...Silisk, 22......Gate control circuit section. 8 l Kasumigiku, 3 figures ((1) (b) (C) (d) 4 days (α) (b) 8 motions?
￥9? No. S l, i No. 6, 7, 7 (a,) Taku (α) δ ki<b) 9 Figure (b') 2

Claims (3)

[Claims] (1) In a method of controlling a self-arc-extinguishing thyristor, the electric charge stored in the first capacitor when the self-arc-extinguishing thyristor is non-conducting is transferred to the second capacitor when the self-arc-extinguishing thyristor is conducting, and the turn-off conducting means is made conductive when the self-arc-extinguishing thyristor is non-conducting. The self-arc-extinguishing type is characterized in that the self-arc-extinguishing thyristor is extinguished by the discharge current of the second capacitor that flows at the same time, and the first capacitor is charged so that the self-arc-extinguishing thyristor is cut off next time. How to control a thyristor. (2) Connect one end of the first capacitor to the 7-note terminal of the self-extinguishing thyristor, and connect the second capacitor to the cathode terminal.
one end of the capacitor is connected, one end of the turn-off switch is connected to the gate terminal, and the other end of the first capacitor, the other end of the second capacitor, and the other end of the turn-off switch are commonly connected. A control device for a self-arc-extinguishing thyristor. (3) The first terminal is connected to the anode terminal of the self-extinguishing thyristor.
one end of the capacitor is connected to the cathode terminal, and one end of the second capacitor is connected to the cathode terminal, and the anode electrode of the thyristor is connected to the gate terminal, and the cathode electrode is connected in parallel to the second capacitor to the self-extinguishing thyristor. A diode is connected so as to be common to the cand of the first capacitor, the other end of the first capacitor is connected to the other end of the second capacitor, and the anode electrode of the diode is connected so as to be common to the cathode electrode of the thyristor. A control device for a self-arc-extinguishing thyristor.