JPS605755Y2 - Ignition pulse generator - Google Patents

Description

[Detailed explanation of the idea] This invention relates to an ignition pulse generator.

For example, it may be required to repeatedly ignite the ignitron at intervals of several milliseconds or less.

In such a case, the ignition pulse must also be generated at a correspondingly fast cycle.

Generally, a configuration as shown in FIG. 1 is used to generate this type of ignition pulse with a simple configuration.

In the figure, 1 and 2 are AC power supply terminals, 3 is a DC generator, 4 is a charging resistor, 5 is a capacitor, and 6 is a thyratron for ignition (or it may be a thyratron).

), 7 is its gate, 8 is a current limiting resistor, 9 is an ignitron, and 10 is an igniter.

According to this configuration, the electric power supplied from the AC power supply terminals 1 and 2 is converted into DC by the DC generator 3.

The capacitor 5 is then charged by this direct current.

In order to ignite the ignitron 9, it is sufficient to apply a gate pulse to the gate 7 of the thyristor 6 to make it conductive, and at that time, the capacitor 5 that has been charged up to that point will be connected to the thyristor 6, the resistor 8, and the igniter 10. This causes an ignition pulse to be applied to the ignitron 9, causing it to fire.

When the combined current of the discharge current of the capacitor 5 and the DC current flowing from the DC generator 3 through the resistor 4, thyristor 6, resistor 8, and igniter 10 becomes less than the time-keeping current of the thyristor 6, the thyristor 6 is turned off. .

Therefore, with this configuration, the resistance value of the charging resistor 4 cannot be made very small, and if the time-keeping current of the thyristor 6 is small, the AC input must be temporarily turned off on the AC power supply terminals 1 and 2 side.

Due to these restrictions, a considerable amount of time is required from once the capacitor 5 is discharged until the next charge is completed, and therefore the repetition period of the ignition pulse cannot be shortened.

The purpose of this invention is to generate an ignition pulse with a sufficiently short period using a simple configuration.

This invention is characterized in that when generating a desired firing pulse using a thyristor, two firing pulses are generated each time a gate pulse is applied to the thyristor to make it conductive.

According to this, when the gate pulse of the thyristor is repeatedly applied, an ignition pulse can be generated with a cycle that is half of the repetition cycle.

An embodiment of this invention will be explained with reference to FIG.

Note that parts given the same reference numerals as in FIG. 1 indicate the same or corresponding parts.

In Fig. 2, 11 is a thyristor, 12.13 is a capacitor for commutation of thyristor 6.11, 14 is a balance transformer for commutation, and 15.16 is an integration circuit for determining the time limit t shown in Fig. 3. 17 is a resistor that limits the gate current of the thyristor 11, 18 is a diode for preventing reverse voltage from being applied to the gate of the thyristor 11, and 19 is a resistor and a capacitor that constitute the thyristor 6.
20 is a resistor for charging the capacitor 12.13.

The resistance value of the resistor 20 is sufficiently small compared to that of the charging resistor 4, and the capacitance of the capacitors 12 and 13 is sufficiently small compared to that of the capacitor 5.

21 is a resistor, and 22 is a diode connected to the igniter 10.

In the above configuration, it is assumed that initially thyristor 11 is in a conductive state, thyristor 6 is in a non-conductive state, and capacitor 12 is charged to the same voltage as capacitor 5.

If the gate pulse P is applied to the gate of the thyristor 6 to make it conductive, the capacitor 12 will be discharged through the upper half of the thyristor 6 and the transformer 14.

As a result, a voltage is induced in the lower half of the transformer 14, and if the winding ratio of the upper and lower halves is 1, a voltage twice as high as the voltage in the upper half will be induced at both ends of the transformer 14.

This voltage is applied to the diode 22, resistor 21, and igniter 10.
The first ignition pulse P is applied to the ignition pulse P.

On the other hand, the capacitor 13 is charged by the voltage induced in the lower half of the transformer 14, and at the same time, a reverse voltage is applied to the thyristor 11 to make it non-conductive.

Even after the thyristor 11 becomes non-conductive, the current from the capacitor 5 flows through the resistor 20, the thyristor 6, and the transformer 14.
The current flows through the upper half of the circuit leading to the capacitor 13 and charges the capacitor 13.

When the voltage of the capacitor 13 charged in this way passes a time limit t determined by the time constant determined by the resistor 15 and the capacitor 16, a gate pulse is applied from the capacitor 16 to the gate of the thyristor 11, and the thyristor 11 is made conductive.

Due to this conduction, capacitor 13 is discharged, and transformer 1
Since that voltage is applied to the lower half of the thyristor 4, a voltage is also induced in its upper half, and this voltage causes the thyristor 6 to be non-conductive.

Also, the voltage across the transformer 14 is again applied to the igniter 10, and a second ignition pulse P2 is now applied.

Note that even after the capacitor 13 has finished discharging as described above, the resistor 20. Through the resistor 19, transformer 14, and thyristor 11, a holding current is supplied to the thyristor 11 to maintain its conductive state.

The above-mentioned operation is then repeated. As described above, it is possible to generate two ignition pulses by just applying one gate pulse, so it is possible to generate ignition pulses at a shorter period than the gate pulse period, and the ignition pulse is reduced accordingly. It becomes possible to shorten the repetition period.

If the repetition period of the gate pulse is shortened within a range that does not cause a voltage drop in the capacitor 5, the repetition period of the ignition pulse will be shortened accordingly.

As understood from the above description, the resistor 4 and capacitor 5 may be omitted, and the capacitor 12 and the like may be charged by the direct current from the DC generator 3 via the resistor 20.

As detailed above, according to this invention, two firing pulses are generated by giving one gate pulse to the thyristor, so the firing pulses are generated at a cycle shorter than the gate pulse cycle. Therefore, by making the period of the gate pulse sufficiently short, it is possible to generate the ignition pulse at an extremely short period.

[Brief explanation of drawings]

FIG. 1 is a conventional circuit diagram, FIG. 2 is a circuit diagram showing an embodiment of this invention, and FIG. 3 is a waveform diagram for explaining the operation. 3... DC generator, 6... First thyristor, 11... Second thyristor, 12...
...First capacitor, 13... Second capacitor, 14... Balance transformer, 15
．． 16... Resistor and capacitor for the integration circuit.

Claims (1)

[Scope of utility model registration request] A first thyristor (or thyratron) connected to the positive side of the DC output end in a forward direction with respect to the DC output and made conductive by a gate pulse; a resistor connected in parallel to the first thyristor so as to cause a time-keeping current to flow through the second thyristor when the second thyristor connected to the first thyristor is non-conductive; a balance transformer for commutation of each of the thyristors connected across the thyristor; a capacitor for first commutation connected across one half of the balance transformer and the first thyristor; and the balance transformer. a second commutation capacitor connected across the other half of the second thyristor and the voltage of the second capacitor and applying a gate pulse to the second thyristor at a predetermined time period; An ignition pulse generator comprising a circuit, and configured to generate an ignition pulse using the induced voltage of the balance transformer.