JPH0833311A - Abnormal element detector for a plurality of self-extinguishing thyristors connected in series - Google Patents

Abstract

PURPOSE:To detect abnormality at the lower voltage part in a gate circuit each of a plurality of self-extinguishing thyristors connected in series by comparing the output level of a gate off signal command with the level of bias voltage on the output side of a gate off switch. CONSTITUTION:A failure detection circuit 76 is connected in parallel on the switch 75 side in the gate circuit 61, 62, 63 each of a plurality of self- extinguishing thyristors 11, 12, 13 connected in series. The failure detection circuit 76 has one input receiving a gate off signal 732 and the other input receiving a gate off signal command 733 from a driver 73 upon provision of a control signal 511 during OFF interval. The failure detection circuit 76 compares the gate off signal 732 with the gate off signal command 733 and delivers a failure detection signal 760 if an abnormality is detected. Since the abnormality is detected at the low voltage part in the gate circuit 61, 62, 63 and the thyristor is stopped, high voltage division is not required.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an element abnormality detecting device for a plurality of series-connected self-extinguishing thyristors which detects an abnormality of an element in a high voltage and large capacity power converter.

[0002]

2. Description of the Related Art In a high voltage and large capacity power converter, a GT
A highly redundant system in which a plurality of self-extinguishing thyristors (hereinafter referred to as elements) such as O thyristors and SI thyristors are connected in series is applied. In such an element group in which a plurality of elements are connected in series, when one of the elements fails, the shared voltage of the remaining elements increases and the overvoltage is activated, and thus the elements may be destroyed. As this type of failure detection device, the one shown in FIG. 5 is known.

FIG. 5 shows a partial configuration of a high-voltage and large-capacity power converter shown for explaining a conventional example. Reference numerals 11, 12, and 13 denote three serial connection elements, 2 is a control circuit, and 3 is an element 11. , 12, 13
It is a gate circuit arranged in each. In the element 11, A is an anode, K is a cathode, and G is a gate. Reference numerals 41, 42 and 43 are light emitting diodes connected in parallel to the elements 11, 12 and 13, respectively.

That is, the control signals 211, 2 of the control circuit 2
Devices 11,1 by gate circuits 31,32,33 to obtain 12,213
Although the high-voltage and large-capacity power converters based on 2 and 13 are publicly known and the description thereof is omitted here, the device for detecting the failure of the element part is between the elements 11, 12, and 13 (AK). The optical signals 411, 421, 431 emitted by the respective light emitting diodes (photocouplers) 41, 42, 43 provided are passed through an optical fiber, converted into an electric signal by the control circuit 2, and then a failure occurs depending on the state of the electric signal. Is to be monitored.

[0005]

In this type of prior art, the elements 11, 12, 13 on the main circuit side to which a high voltage is applied are applied.
When the light emitting diodes 41, 42, 43 are mounted in parallel between the terminals of, the light emitting diode is mounted at a place near or a little away from the high voltage circuit part, and the light emitted from the light emitting diode is detected by the optical fiber. Therefore, high voltage is also applied to the wiring from the terminals of the element to the light emitting diode, which is dangerous. Moreover, the wiring around the element is also complicated in this way.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and is provided between each (gate and cathode) of a plurality of series-connected elements that constitute a high-voltage large-capacity power converter. Inside each connected gate circuit, a special failure detection signal is obtained by comparing the OFF signal command and the output side of the gate OFF switch, and such a gate circuit can be configured to output a signal to the control circuit. It will be.

[0007]

By the means for solving the problems, the following operational effects can be obtained. That is, in each gate circuit, when the element is normally off, an off bias is applied between the elements (gate and cathode), and it is possible to determine whether or not there is a failure by comparing the off signal command of the driver output and the gate off signal.
When it is determined that there is a failure, the failure detection signal is transmitted to the control circuit. Hereinafter, the present invention will be described in more detail with reference to the drawings.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is similar to FIG. 5 for facilitating the understanding of the technical idea of the present invention, and 5 is a control circuit, 61, 6
Reference numerals 2 and 63 are gate circuits. Here, each of the gate circuits 61, 62 and 63 for obtaining the control signals 511, 512 and 513 of the control circuit 5 drives the elements 11, 12 and 13 and acts as a high voltage and large capacity power converter. Is the same as.

In each of the gate circuits and control circuits, failure detection circuits 611, 621, 631 are arranged inside each of the gate circuits 61, 62, 63, and failure detection signals 612, 612 622 and 632 are output to the control circuit 5, so that the control circuit 5 can monitor the failure. This will be described with reference to FIGS.

FIG. 2 shows an example of a gate circuit having a failure detection circuit, and 7 is each gate circuit 6 shown in FIG.
It is a gate circuit that can be used for 1, 62 and 63. In the gate circuit 7, 71 is an on-bias power supply, 72 is an off-bias power supply, 73 is a driver, 74 and 75 are switches using FETs, and 76 is a failure detection circuit. That is, in the gate circuit 7, the control signal output from the control circuit 5
511 is input to the driver 73. When the signal is on, the switch 74 is turned on by the gate-on signal 731 based on the gate-on command, and the voltage of the on-bias power supply 71 is turned on.
Apply between 11 (G-K). When the signal is off, the switch 75 is turned on by the gate off signal 732 generated based on the gate off signal command 733 to turn off the off bias power supply.
72 is applied between (G-K) to turn off the element 11.
Furthermore, in the gate circuit 7, the switch 75 side (FET G
The failure detection circuit 76 is connected in parallel between (-D). Reference numeral 760 is a failure detection signal. This is shown in FIGS. 3 and 4.

FIGS. 3 and 4 show an example of a failure detection circuit and a timing chart of its signal output, where 761 is a photocoupler and 762 is a comparator. In the fault detection circuit 76 shown in FIG. 3, the photocoupler 761 outputs a gate-off signal 7 to the switch 75 for off-bias.
Detect 32. The comparator 762 receives the gate-off signal 732 as one input, and the gate-off signal command 733 obtained when the driver 73 is turned off from the control signal 511 input as the other input. Generates a fault detection signal 760. That is, as shown in FIG. 4, it is normal when the gate-off signal command 733 is "H", the gate-off signal 732 is "L", the gate-off signal command 733 is "L", and the gate-off signal 732 is "H". Gate-off signal
When the 733 is "L" and the gate-off signal is 732 "L", it is considered that there is an abnormality in the element, and the failure detection signal 760 is "L".
To "H" and a signal can be generated.

To explain this more concretely, in the gate circuit 7, when the element 11 is normal and is off, a bias is applied between (G-K) of the element 11 and the switch 75 ( The gate-off signal 732 of about (+5 V) is output from the driver 73 also during G-S). As a result, when the element 11 fails, no bias is applied during (G-K), and the gate-off signal 732 between (G-S) of the switch 75 also becomes (OV), and the failure detection signal 760 can be obtained. it can.

Further, it goes without saying that such an embodiment is as follows. (1) The failure detection circuit in the gate circuit provides the control circuit with the fact that each of the elements has been short-circuited due to element destruction. As a device, all the remaining elements are on and the current is cut off by another protective device. Can be easily applied depending on the circuit configuration, such as applying a gate block to the device, or applying a gate block to the remaining elements after receiving the respective failure detection signals to stop the device. (2) When the power supply for operating the gate circuit in each gate circuit fails, a signal voltage is not output during (DS) of the switch, a short circuit occurs, and the level is detected by the failure detection circuit. When the power supply for operating the circuit is lost, the gate signal is not sent to the element and the element is no longer off-biased, preventing the possibility of element destruction from overvoltage due to an increase in the shared voltage of the remaining elements, The device can be stopped. (3) Even if the control signal cannot be transmitted to the gate circuit of each element due to a failure of the control circuit or a short circuit of the wiring from the control circuit to the gate circuit, the above-mentioned overvoltage protection can be realized.

[0014]

As described above, according to the present invention, even if one of a plurality of elements connected in series is broken, an abnormality can be detected in the low voltage portion in the gate circuit, so that high voltage partial pressure and the like can be achieved. It is possible to provide a device having a simple structure that can be easily and easily implemented by eliminating the need for detecting abnormality of each element and including overvoltage protection of the remaining elements.

[Brief description of drawings]

FIG. 1 is a system diagram shown to facilitate understanding of a technical idea of the present invention.

FIG. 2 is a system diagram showing a main part configuration of an embodiment of a gate circuit according to the present invention.

FIG. 3 is a system diagram showing an example of the failure detection circuit of FIG.

FIG. 4 is a timing chart shown for explaining FIG.

FIG. 5 is a system diagram showing a partial configuration of a conventional power converter.

[Explanation of symbols]

 11 Self-extinguishing thyristor (element) 12 Self-extinguishing thyristor (element) 13 Self-extinguishing thyristor (element) 2 Control circuit 31 Gate circuit 32 Gate circuit 33 Gate circuit 41 Light emitting diode 42 Light emitting diode 43 Light emitting diode 5 Control Circuit 61 Gate circuit 62 Gate circuit 63 Gate circuit 611 Failure detection circuit 612 Failure detection circuit 613 Failure detection circuit 7 Gate circuit 71 On-bias power supply 72 Off-bias power supply 73 Driver 74 Switch 75 Switch 76 Failure detection circuit 761 Photocoupler 762 Comparator

Claims (1)

[Claims] 1. A power converter comprising a plurality of self-extinguishing thyristors connected in series, wherein a gate-off signal command output level and a gate-off switch output are provided in a gate circuit of each self-extinguishing thyristor connected in series. A device abnormality detecting device for a plurality of series-connected self-extinguishing type thyristors, characterized in that means for comparing the bias voltage levels on the side is provided, and the output of the comparing means is obtained as a failure detection signal.