JPS58195318A - Voltage detector of series thyristor - Google Patents

Abstract

PURPOSE:To attain a voltage detector having high reliability in comparison with conventional detectors, by inserting an AND element between a reception section and an output section, and inputting the output of the reception section directly or via a one-shot multivibrator. CONSTITUTION:If an amplifier 7d has failed and no output is obtained, since the one-shot multivibrator 9d and the AND element 10d produce no output but other one-shot multivibrators 9a-9c and AND elements 10a-10c give an output, a reverse voltage detection signal (e) is outputted from an OR element 8. Thus, when detection elements 1 and a path leading the output to the output section are normal, it is detected in the circuit 1 that the reverse voltage of thyristors is applied. Conversely, if an amplifier 7d, for example, has failed at the conduction of the thyristors 1a-1d and the said amplifier 7d produces a failure signal, the failure signal is blocked substantially with the one-shot multivibrator 9d and an AND element 10d.

Description

[Detailed description of the invention] The present invention relates to a voltage detection device for a series thyristor.

A conventional example of this type of voltage detection device is shown in FIG. Light emitting diodes 21 to 2d are inserted in parallel. 31 to 3d are limiting resistors provided to protect the light emitting diodes 2a to 2d, respectively.

The light emitting diodes 28 to 2d output optical signals when a reverse voltage is applied to the thyristors 11 to 1d. Optical signals from the light emitting diodes 18 to 1d are transmitted to photoelectric converters 6a to 6d of the receiving units 5a to 5d on the low potential side by light guides 4a to 4d, respectively, which constitute transmission paths. Light th, converter 68~
The outputs of 6d are amplified by amplifiers 71 to 7d, respectively, and then outputted through the OR element 8 of the output section.

In this conventional device, when the reverse voltage of the thyristors 1a to 1d is applied to the circuit 1, a signal indicating the application of the reverse voltage is sent through each path including the light guide, the photoelectric converter, and the amplifier. During the directional voltage application time TA, the OR element 8
is input to the logical OR element 8, and a reverse voltage detection signal e is output from the OR element 8. However, even if an abnormal signal occurs in one of the plurality of paths for some reason when the reverse voltage is not applied, The abnormal signal is a reverse voltage from the OR element 8,
This has the drawback that a malfunction occurs in that it is output as the detection signal e.

This invention was made to eliminate the drawbacks of the conventional ones described above, and includes an AND element inserted between a receiving section and an output section, and the output of the receiving section is directly transmitted to the AND element. The purpose of this invention is to provide a voltage detection device for series thyristors that is more reliable than the conventional one by manually performing one-shot multiplexing.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, reference numerals 9a to 9d are one-shot multi-channel amplifiers, which are driven by the outputs of amplifiers 1a to 7d, respectively. The one-sided multipliers 91 to 9d are configured such that the time width TB of their output is slightly larger than the reverse voltage application time TA.

10a to 10d are AND elements, which receive the outputs of the one-shot multis 9a to 9d and the outputs of the amplifiers 7a to 7d, respectively, and cooperate with the corresponding one-shot multis 9a to 9b to block an abnormal signal. Configure.

The outputs of the AND elements 10a to 10d are input to the OR element 8. The other configurations are the same as those in FIG.

In this configuration, there are 2 light emitting diodes & 4 m light guides.
, photoelectric converter 6a1 amplifier 71, one-shot multi 9
m, if there is no abnormality in the AND element 10m, the one-shot multi 9a outputs when a reverse voltage is applied to the thyristor 1a, and since TB)TA, the logical building block is The output terminal 10m outputs a reverse voltage detection signal e. The same applies when the output paths of the other light emitting diodes 1b to 1d are normal. A time chart of the output of each part during normal operation is shown in Figure 3. In the figure, T1 to T3 are respectively times IJ,
j: represents.

In this state, if, for example, the amplifier 7d fails and does not output, the one-shot multiplier 9d as shown in FIG.
, the AND element 10d does not output l, but the other one-shot multiplexers 9a to 9c and m buried elements 10a to 10C output, so the reverse voltage detection signal e is generated from the OR element 8. As shown in Figure @5, even if the one-shot multi 9d fails and no longer outputs, the reverse voltage detection signal e is similarly output. Therefore, if the first detection element and the path leading its output to the output section are normal, it is detected that the reverse voltage of the thyristor is applied to the circuit 1.

Conversely, when the thyristors 11L to 1d are conductive, for example, if an abnormality occurs in the amplifier 7d and the amplifier 1d outputs an abnormal signal, the abnormal signal will continue until the cause of the abnormality is removed. Therefore, this abnormal signal passes through the OR element only during the time TB, but is not input to the OR element thereafter, and is substantially blocked by the one-shot multi 9d and the AND element 10d.

As described above, according to the present invention, a one-shot multi and an AND element are inserted in series between each receiving section and an output section, and the input and output of the one-shot multi are connected to the input and output of the AND element. With this configuration, even if an abnormal signal is generated when the thyristor is not receiving reverse voltage due to a failure in the receiving section, etc. in the path between the light emitting diode and the output section, the abnormal signal will be effectively suppressed. , the reliability can be improved compared to the conventional method.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional series thyristor voltage detection device, FIG. 2 is a circuit diagram of an embodiment of a series thyristor voltage detection device according to the present invention, and FIGS. 3 to 5 show the operation of this embodiment. 2 is a time chart of various signals for explaining. In the figure, 18-1d...thyristor, 2a-2d
...Light emitting diode, 4a to 4d...Transmission line, 5a
~5d... Receiving section, 8... OR element, 9a to 9d
. . . One-shot multi, 10a to 10d . . . AND element. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Shin Kuzuno - 7d Fuchibetsu I T2

Claims (1)

[Claims] In a voltage detection device for a series thyristor, the voltage detection device includes a light emitting diode inserted between the anode and docker electrodes of each series thyristor, and a receiving section that receives an optical signal output from each light emitting diode and converts it into an electric signal. A one-shot multi is provided at the next stage of the receiving section, and an AND element is provided to receive the output of the one-shot multi and the output of the receiving section, and the output of the one-shot multi is not smaller than the output of the receiving section. A voltage detection device for a series thyristor characterized by having a time width.