JPS61270915A - Off gate circuit of gto - Google Patents

Abstract

PURPOSE:To set a dynamic frequency high in frequency range by providing plural circuits to discharge a stored charge in a capacitor and to make flow an off-gate current of a gate turn-off thyristor (GTO), and attaining alternate operation. CONSTITUTION:When an input signal S1 is supplied, an FF10 is inverted, a terminal S2 goes to an H level and a transistor (TR) 5a is turned on for a prescribed time via a waveform shaping circuit 9a, and the electric charge charged in a capacitor 4a is discharged through an input winding N2a of a pulse transformer. Thus, an off-gate current is fed to the gate of the GTO 1 via diodes 7a, 7b from the output winding of the pulse transformer to turn off the GTO 1. The electric charge in the capacitor 4a is discharged by supplying the input signal S1 after the GTO 1 is turned on the turn off the GTO 1, plural off-gate circuits are provided to apply alternate driving thereby allowing sufficient charging time of the capacitor, the the off-gate current is supplied stably and the dynamic frequency can be set at a high frequency range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field of the invention] The present invention relates to a gate turn-off tiller (hereinafter referred to as GTO).
Improvement of the off-gate circuit (2) to control the off-gate current (2), especially (2) the effect of increasing the operating frequency limit determined by the time required for charging the capacitor that supplies the off-gate current (2) A certain GTO off-gate circuit (= related to.

[Technical background of the invention and its problems]

Conventionally, as an off-gate circuit of GTO, the circuit shown in Fig. 4 (:) is used as an off-gate circuit using a pulse transformer. is connected to its cathode (two) via diodes 7- and 7b.The gate power supply 3 is connected to the primary winding N1 of the pulse transformer 2 via the diode 6.
The other end of the primary winding Nl is connected to one end of the primary winding N and the capacitor 4.
connected to one end of the The other end of the primary winding Nt is connected via the transistor 5 to the other end of the capacitor 4 and to the gate' wax source 3.
minus at=connected. Figure 5 ia) is the trough waveform at the time of operation of the circuit in Figure 4 (2). (I) is
The voltage waveform across the capacitor 4, (II) is the off-gate current output from the secondary winding N3 of the pulse transformer 2;
(1) is 1. It is a voltage waveform between the gate and cathode of GTO element 1. At time t0, the transistor 5 (when the two-pace signal is supplied, turns on the transistor 5, and the electric charge charged in the capacitor 4 is transferred to the primary winding N1 of the pulse transformer 2, It discharges through the transistor 5 and generates a voltage in the secondary windings N and I.
The output current IQff from the secondary winding Ns is passed through diodes 7, . 7b, a negative current is output from the GTO element power source to the gate. time to
During the time Toff from txt to txt, the base signal is applied to the transistor 5, and the transistor 5 is turned on. After the time TOFF has passed, the transistor 5 is turned off at time 11, and the exciting current of the pulse transformer 2 is applied to the positive side of the gate power supply 3, the diode 6, and the primary winding N during the time T6 from time t8 to time t. .

, the capacitor 4, the gate"[flows in the negative side circuit of the source 3, and recharges the content 4. The equivalent circuit at this time is shown in Figure 5(b). ゛In recent years, GTO has been used. In the converter, there is a need to increase the switching frequency of the GTO for PWM control, etc. In this case, there is a limit to the operating frequency due to the capacitor charging time T6 of the off-gate circuit and the off-current output time. If the off-current output signal is output and the transistor 5 is turned on before charging is completed, sufficient gate current Iou will not be output, and a failure may occur in which the GTO element fails to turn on or off and is damaged.

[Purpose of the invention]

The purpose of the present invention is to construct a part or all of the off-gate circuit by multiplexing the above-mentioned point (2). The purpose is to provide an off-gate circuit.

[Summary of the invention]

In the present invention, at least two or more sets of off-gate circuits are provided, and they are sequentially driven to obtain a predetermined output frequency. The circuit operation is twice that of the conventional example.

[Nine examples of inventions]

Figure 1 (2) shows an example of the present invention. Portions C that are the same or equivalent to those in Figure IJ14 are the same reference numerals and the letter a.

b is added to distinguish them, and the explanation thereof will be omitted. The clip-flop lO outputs the input signal S (N number Sza * So
waveform shaping circuit 91t 9. , from the second, the signal S. .

Output Ssb and set transistor 5□l 5b to 1800
It is configured to drive with a phase shift.

Next, the operation of the present invention will be explained with reference to FIG. 1 and FIG. 2 showing waveforms of various parts during operation and a time chart of No. 48. As the input signal St of the clip-flop 10, G
The switching frequency of TO (=corresponding clock pulse is supplied. The output of 7 lip 70 lip IO is Sea
*13*b 11- becomes an inverted signal and becomes an input signal of the waveform shaping circuit 9at9b. Waveform shaping circuit 9□9
The output of b outputs a square wave pulse that determines the off-gate pulse width of Ssa+Ssb, whose phases are mutually (2180
'The pulse signal will be shifted. The signal Ssa drives the υ transistor, which is the base signal of the transistor 51, and the signal Ssb is the base signal of the transistor 5b. Switching ζ of transistors 5atSb driven with phases shifted by 180° from each other, diodes 7, .

7b * 8@e Through 8b, the output winding Nsa + NR of the parallel (two-wired pulse transformer 2..2b)
The output frequency of the off-gate current l0ff, which is synthesized from winding B and supplied to the gate of GTO1, is the content of one circuit in duplex circuit C, which drives with a phase shift of 180'. 41. And 4° charge * 1 = required time of 3A (2) can be taken, so the operating frequency can be increased to twice that of the conventional one.

The circuit configured by duplication may be configured as shown in Fig. 3 by integrating the pulse transformer.The operation is the same as in Fig. 1.In this case, the pulse transformer 2 is configured as a single circuit. Compared to when the circuit was configured, the applied voltage time product is pa71Fl.
Therefore, since the capacitor 4at41i is overcharged, the diode 12. in FIG. 3 is connected to suppress the charging voltage.
, 12. , the valley, and the capacitor too.

4- and the auxiliary power source 310 (two connections, overcharge):
I'm going to absorb it 51; A Zener diode may be used in place of the auxiliary power supply 31, or, as shown in FIG. Good too.

Further, a pulse transformer configuration may be adopted in which a plurality of sets of the primary side circuits shown in FIG. 4 are provided.

〔Effect of the invention〕

As described above, according to the present invention, by configuring off-gate circuits by multiplexing them, it is possible to provide an off-gate circuit that is effective in increasing the operating frequency.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a time chart showing a description of each part to explain the operation of FIG. 1, and FIG. 3 is a diagram showing another embodiment of the present invention. FIG. 4 is a block diagram showing an example of the configuration, FIG. 4 is a block diagram of a conventional off-gate circuit, and FIG. 5 is a waveform diagram of various parts for comparison to explain the operation of FIG. 4. 1...GTOl 2,2a*2b...Pulse transformer, 3...Gate power supply, 4*4m + 4b
... Capacitor, 5 + 5m + sb ... Transistor, 6 * 6m + 6b ... Diode, 7□7b * 8a + 8b ... Diode, 9a * 9b ... Waveform shaping circuit, 10 ...・
Flip frog, 114°11b...diode,
12. , 12b...Diode (7317) Agent Patent attorney Kensuke Chika (and 1 other person) Figure 1 Figure 2

Claims (1)

[Claims] (1) In a GTO off-gate circuit configured to accumulate charge in a capacitor and output an off-gate current by discharging the charge, at least two or more sets of the above-mentioned off-gate circuits are provided and driven alternately to achieve a predetermined output frequency. 1. A GTO off-gate circuit characterized in that it is configured to obtain a GTO off-gate circuit.