JPH01120912A - Gate circuit of gate turn-off thyristor - Google Patents

Abstract

PURPOSE:To charge each capacitor momentarily and to flow a normal ON high gate current at the high frequency switching operation by charging a 1st capacitor and a 2nd capacitor for ON high gate current while using one terminal of the capacitors as a negative potential. CONSTITUTION:A 1st switch 19 and a 2nd switch 20 are provided respectively to a common part of the 1st capacitor 8 and the 2nd capacitor 9, the 1st switch 19 is connected to zero potential and the 2nd switch 20 is connected to a negative potential. In turning off the ON gate switch 12 and turning on the OFF gate circuit 13, a negative OFF gate current is fed to a GTO 1. Simultaneously, the 1st switch 19 is turned off and the 2nd switch 20 is turned on to bring the common part of the 1st and 2nd capacitors 8, 9 to a negative potential, and the 1st capacitor 8 through the 3rd charging diode 18 and the 1st charging diode 6, and the 2nd capacitor 9 through the 4th charging diode 17 are charged momentarily up to the ON gate power voltage respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gate circuit that controls turning on and off of a gate turn-off thyristor.

[Conventional technology]

FIG. 3 shows, for example, a conventional gate circuit shown in Japanese Patent Application No. 61-253336, and in the figure, 1 is a gate turn-off thyristor (hereinafter referred to as GTO),
G is a gate electrode, and K is a cathode electrode. Reference numeral 2 denotes a chip circuit, which includes a chip switch 14 for switching the on-gate power supply 3. It is comprised of a current detection means 16 for detecting the output current of the chipper circuit 2 and a freewheeling diode 15. 11 is a reactor, which is composed of a primary winding 11a and a secondary winding 11b. 8 is a first capacitor, 9 is a second capacitor, and 10 is a resistor. 12
is an on-gate switch, which supplies the output currents of the chopper circuit 2 and the first capacitor 8 to the GTOl as on-gate currents. A diode 6 is used to charge the first capacitor 8, and a diode 7 is used to charge the second capacitor 9. 13 is an off-gate circuit that supplies an off-gate current to GTOl. Further, 4 is an off-gate power supply.

Next, the operation will be explained. The chopper circuit 2, which constitutes the on-gate power supply in combination with the on-gate power supply 3, has a constant current control function, and controls the gate current Ig by the current detection means 1.
6, and by adjusting the conduction ratio of the switch 14, the value of the on-gate current is kept constant. The free-wheeling diode 15 is conductive when the carbon dioxide collar switch 14 is off, and functions to continue the gate current via the reactor 11. On-gate switch 12
When GTOl is off, an off-gate current is supplied from the off-gate circuit 13 to GTOl.

The case where the on-gate switch 12 is turned on and off will be explained with reference to the operation waveform diagram shown in FIG. 4. Before time t1, the on-gate switch 12 is off, and the first collar switch 14 turns on and off.
．． The second capacitors 8 and 9 are charged to the illustrated polarity through the primary winding 11a of the reactor 11.

At time t1, when the on-gate switch 12 is turned on, the gate current Ig converts the discharge current Ic of the first capacitor 8 and the discharge current of the second capacitor 9 into the reactor 1.
It flows as the sum of the imaging current Ice obtained by flowing it through the secondary winding 11b of No. 1.

At time t2, the voltage Ec9 of the second capacitor 9 decreases, and the voltage generated in the primary winding 11a of the reactor 11 (generated with a ratio of 1:n and opposite polarity to the power supply) becomes lower than the voltage of the on-gate power supply 3. When the current in the reactor 110 secondary winding 11b becomes lower, the current in the reactor 110 primary winding 11a
Transfer to. Assuming that the winding ratio of the primary winding 11a and the secondary winding 11b of this reactor 110 is, for example, 8:1,
The output current ICH of the chopper circuit 2 is at time t2,
ICE = Ice/B and starts flowing. Actually,
It is desirable to determine the winding ratio of the reactor 11 so that the initial value of the primary winding 11a of the reactor 110 matches the constant current control value of the chip tube circuit 2.

After time t2, the gate current Ig flows as a substantially constant current due to the constant current control function of the tipper circuit 2.

At time t, by turning off the on-gate switch 12 and turning on the off-gate circuit 13, a negative off-gate current as shown is supplied to the GTOI.

On the other hand, the first capacitor 8 is connected through the reactor/I/110 primary winding 11a1 diode 6, and the diode 7
The second capacitor 9 is charged to the on-gate power supply 3 through the second capacitor 9 .

ICH does not flow after t4.

In addition, in the above embodiment, a conversion method using a combination of the on-gate power supply 3 and the chopper circuit 2 as a DC power supply is shown as having the function of constant current control of the on-gate current, but other known high-frequency AC power supplies may also be used. The constant on-gate current generation source may have a constant current control function by controlling the phase with a mag-amp, and may be a DC output converter. Good to have.

[Problem that the invention seeks to solve]

Since the gate circuit of the conventional gate turn-off thyristor is configured as described above, the charging current is controlled by the first . Second
When charging the capacitors 8 and 9, it is limited by the reactor 11, and it is necessary to allow the current to flow for more than a certain period of time. During high frequency switching operation, the ON signal is input while the charging voltage of each capacitor 8 and 9 is insufficient, resulting in normal operation. There were problems such as the on-high gate current not flowing.

This invention was made to solve the above-mentioned problems, and provides a gate circuit for a gate turn-off thyristor that can instantly charge each capacitor and allow a normal on-high gate current to flow during high-frequency switching operation. The purpose is to obtain.

[Means for solving problems]

The gate circuit according to the present invention includes a first capacitor and a second capacitor.
A first switch and a second switch are respectively provided at the common part of the capacitors, and the first switch is connected to the O potential and turned on when the first capacitor and the second capacitor are discharged, and the second switch is connected to the O potential. The switch is connected to a negative potential so that it is turned on when the first capacitor and the second capacitor are charged, and a charging diode is provided so that the above-mentioned This allows each capacitor to be charged instantly.

[For production]

The charging for the on-high gate current in this invention is carried out by the second
When the switch is on, by setting one end of the first capacitor and the second capacitor to a negative potential, charging can be performed instantaneously from the OK level through the charging diode.

[Embodiments of the invention]

An embodiment of the present invention will be described below.

In FIG. 1, 18 is the third charging diode of the first capacitor 8, and 17 is the fourth charging diode of the second capacitor 9.

19 is a first switch connected between the common portion X and O potential of each capacitor 8, 9; 20 is a first switch connected between each capacitor 8 and O potential;
, 9 and a negative potential. Further, in this embodiment, 6 is a first charging diode, 7 is a second charging diode, and the first switch 19. The first capacitor 8 and the resistor 10 and the first
The parallel circuit with the charging diode 6 constitutes a first series connection, and the second charging diode 7, the second :r/capacitor 9 and the second switch 20 form a second series connection. Configure. Note that other components that are the same as those shown in FIG. 3 are designated by the same reference numerals, and redundant explanation thereof will be omitted.

Next, the operation will be explained. The tilt circuit 2, which constitutes the on-gate power supply 3 in combination with the on-gate power supply 3, has a function of constant @R control, detects the gate current Ig by the current detection means 16, and determines the conduction of the chip-flange switch 14. By adjusting the ratio, the value of the on-gate current is kept constant.

The freewheeling diode 15 is conductive when the chipper section switch 14 is off, and functions to continue the gate current via the reactor 11. When the on-gate switch 12 is off, an off-gate current is supplied from the off-gate circuit 13 to GTol. The case where the on-gate switch 12 is turned on and off will be explained with reference to the operation waveform diagram shown in FIG. 2.

Before time t1, the on-gate switch 12 and the second switch 20 are off, the first switch 19 is on, and the tipper section switch 14 is turned on and off, so that the first
．． The second capacitors 8 and 9 are charged to the illustrated polarity through the primary winding 11a of the reactor 110, the first charging diode 6, and the second charging diode 7. At time t, when the on-gate switch 12 is turned on, the gate current Ig becomes the discharge current Ic of the first capacitor 8, the second capacitor 9 and the reactor 110, and the secondary winding 11.
It flows as the sum of the oscillating current ICC due to b.

At time t2, the voltage of the second capacitor 9 decreases, and the voltage generated in the primary winding 11a of the reactor 11 (
1:n ratio (occurs with opposite polarity of power supply) is on-gate power supply 3
When the voltage becomes lower than the voltage of the secondary winding 1 of the reactor 11
The current of 1b is transferred to the primary winding 11a of the reactor 110. Assuming that the winding ratio of the primary winding 11a and the secondary winding 11b of this reactor 110 is, for example, 8:1, the output current ICH of the windshield circuit 2 is ICH=
It becomes Icc/B and starts flowing. Actually, it is desirable to determine the winding ratio of the reactor 11 so that the initial value of the primary winding j1a of the reactor 110 matches the constant current control value of the chopper circuit 2. After time t2, the -gate current Ig flows as a nearly constant current due to the constant current control function of the chipboard circuit 2. At time t, by turning off the on-gate switch 12 and turning on the off-gate circuit 13, a negative off-gate current as shown is supplied to GTOj. At the same time, the first switch 1
9 is turned off and the second switch 20 is turned on, the common part of the first and second capacitors 8 and 9 becomes a negative potential, and a voltage is passed through the third charging diode 1B and the first charging diode 6. The first capacitor 8 and the second capacitor 9 are instantly charged to the on-gate power supply voltage through the fourth charging diode 1T. Time t
ICH does not flow after 4. In other words, the first capacitor 8 and the second capacitor 9 are instantly charged to a large extent when off-gate current is supplied.

In the above embodiment, a conversion method using a combination of the on-gate power supply 3 and the chopper circuit 2 as a DC power supply is shown as having a constant current control function of the on-gate current, but a known high-frequency AC power supply may also be used. Rather than performing phase control with a mag-amp, it may also have a constant current control function, and the constant on-gate current generation source has a constant current control function and is a DC output converter. Good to have.

〔Effect of the invention〕

As described above, according to the present invention, the first capacitor and the second capacitor are connected to the on-gate power supply via the reactor.
A first switch and a second switch are connected to a common part of the capacitors, the first switch is connected to 0 potential and turned on when the two capacitors are discharged, and the second switch is connected to a negative potential. The capacitors are connected so that they are turned on when the two capacitors are charged, and each capacitor is charged through the charging diode when these capacitors are charged, so that each capacitor is charged instantly. During high frequency switching operation,
This has the effect of allowing a normal on-high current to flow through the GTO.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a gate circuit of a GTO according to an embodiment of the present invention, FIG. 2 is an operation waveform diagram showing the operation of FIG. 1, and FIG. 3 is a circuit diagram showing a gate circuit of a conventional GTO. FIG. 4 is an operation waveform diagram showing the operation of FIG. 3. 1 is a gate turn-off thyristor (GTO), 2 is a chida circuit, 3 is an off-gate power supply, 4 is an off-gate power supply,
5 is a discharging diode, 6 is a first charging diode,
7 is a second charging diode, 8 is a first capacitor,
9 is a second capacitor, 10 is a resistor, 11 is a reactor, 11a is a primary winding, 11b is a secondary winding, 12 is an on-gate switch, 13 is an off-gate circuit, 17 is a fourth charging diode, 18 is the third charging diode, 1
9 is a first switch, and 20 is a second switch. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Figure 1

Claims (1)

[Claims] It consists of a primary winding and a secondary winding, and is configured such that the output ends of the primary and secondary windings are connected to each other, and a coupling effect occurs between the primary and secondary windings. an on-gate power supply having a constant current control function and having a first DC output terminal connected to the input terminal of the primary winding of the reactor; a second DC output terminal of the on-gate power supply; A first series connection consisting of a parallel circuit of a first switch, a first capacitor, a resistor, and a first charging diode connected between the common output terminals of the primary and secondary windings of the reactor. body and the second of the above off-gate power supply.
a second charging diode connected between the DC output end of the reactor and a common output of the primary and secondary windings of the reactor;
A second series connection body consisting of a second capacitor and a second switch is connected to the midpoint between the first switch and the first capacitor and the midpoint between the second switch and the second capacitor. a common part common to each capacitor, a second DC output terminal of the on-gate power supply, and one of the reactors.
A third winding connected between the common output terminal of the next and secondary windings.
a fourth charging diode connected between a second DC output terminal of the on-gate power supply, a discharging diode of the second capacitor, and a midpoint of the second capacitor; A gate circuit for a gate turn-off thyristor, comprising an on-gate switch whose one end is connected to a common output terminal of the primary and secondary windings of the reactor and supplies an on-gate current to the gate turn-off thyristor.