JPH0697835B2 - Thyristor ignition circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thyristor ignition circuit, and more particularly to a highly reliable thyristor ignition circuit.

[Background of the Invention]

The ignition circuit of the thyristor may be required to have high reliability depending on the place where the thyristor is used. For example, in a large-capacity thyristor converter, the failure of the ignition circuit directly leads to the stoppage of the converter, which in turn causes the generator to stop and the power transmission system to break or break. Is required. To improve reliability, the ignition circuit is duplicated. In order to further increase the reliability, triplexing is necessary. However, in the case of tripling, if the logical sum of the tripling outputs is left as it is, when an abnormality occurs in the 1-system, the abnormal signal may appear in the output of the logical sum. For example, when all the three input signals should be low level signals and an abnormality occurs where only one input signal becomes a high level signal, the output of the logical sum becomes a high level signal (abnormal signal). It is inconvenient here. Therefore, it is possible to use a 2out of 3 circuit. The 2 out of 3 circuit is a circuit that outputs the same signal when at least two of the three inputs have the same signal. According to the 2 out of 3 circuit, even if an abnormality occurs in one of the three systems, a normal output can be obtained based on the remaining two systems. However, 1 system remains abnormal, 2 out o
If the f3 circuit continues to be used, and if another system malfunctions, the 2out of 3 circuit will not operate normally and the converter will have to be stopped. That is, at least 2 systems of 2 out of 3 circuits must be normal, and reliability can be improved only in that range.

[Object of the Invention]

An object of the present invention is to provide a highly reliable thyristor ignition circuit.

[Outline of Invention]

When the firing circuit of the thyristor is tripled, three pulse generators that independently output three identical firing signals are provided. The present invention provides a 2 out of 3 circuit that outputs the same signal to the thyristor when at least 2 out of the 3 outputs of this generator are the same signal, and a normal signal of the outputs of the pulse generator is input and an abnormal signal is input. If both of the OR circuit that does not input are provided and the 3 outputs of the pulse generation circuit are normal, the output of the 2 out of 3 circuit is given to the thyristor, and if at least 1 output of the 3 outputs is abnormal, the 2 out of 3 circuit of the above is output. Instead of the output, the output of the OR circuit is given to the thyristor. Therefore, in the present invention, the above
A signal switching circuit for switching between the 2out of 3 circuit and the OR circuit is provided.

The above is the case where the pulse amplifier is driven by the wide-width ignition signal, but a differential circuit is further added when the pulse amplifier is driven by the narrow-width ignition signal. This differentiation circuit is inserted on the output side in the 2 out of 3 circuit. This is because if a differentiating circuit is inserted on the input side, 2 out of 3 outputs will not be output if there is a time difference between the rising edges of the three input pulses. On the other hand, if a differentiating circuit is inserted on the output side, the differentiated signal is output when at least two signals match, so that the pulse can be reliably output with high reliability. Further, in the above OR circuit, a differentiating circuit is inserted on the input side. This is because when one of the three outputs is abnormal and the operation is switched to the OR circuit, another output becomes abnormal, and the abnormality is due to the transition of the signal to the high level. At some point, one erroneous pulse will be output regardless of whether the differentiation circuit is placed on the input side or the output side of the OR circuit, but when it is placed on the input side, the differential signal is differentiated when a normal signal is input. This is because a normal narrow signal is output by the operation, but no signal is output when the signal is input to the output side, which is inconvenient.

Example of Invention

FIG. 1 is a block diagram showing an embodiment of the present invention (this example is for narrow-width firing signal drive, but in the case of wide-width firing signal drive, only the differentiation circuit of FIG. 1 is excluded. It is good.). As shown in the figure, the three pulse generators 1A, 1B and 1C independently generate the thyristor firing signals A, B and C having the same pulse shape. These signals A, B, C are usually 2ou
It is given to the thyristor 8 via the circuit of 2, the differentiating circuit 3, the signal switching circuit 4, the pulse amplifier 5, the light emitting diode 6, and the light guide 7. This is one route. These signals A, B, C are also differentiating circuits 9A, 9B, 9C, AND circuits 10A, 10B, 10C, OR circuit 11, signal switching circuit 4,
It may be given to the thyristor 8 via the pulse amplifier 5, the light emitting diode 6, and the light guide 7. This is another route. When the signals A, B and C are all normal, the former route is taken, and when at least one signal is abnormal, the latter route is taken.

The abnormality monitoring device 12 determines whether the signal is normal or abnormal. The device 12 receives the firing signals A, B, C, respectively, and outputs the normal / abnormal determination signals a, b, c, respectively. Each judgment signal a, b, c is
When the ignition signals A, B and C are normal, they are in the high level state, and when they are abnormal, they are in the low level state. AND circuit 13
Inputs three determination signals a, b, c and outputs a logical product signal thereof to the signal switching circuit 4. Also AND circuit 10A, 10B, 10C
Inputs the firing signals A, B, C and the determination signals a, b, c, respectively, and outputs the logical product signal to the OR circuit 11. Therefore, the OR circuit 11 does not input the signals judged to be faulty among the ignition signals A, B and C, inputs only the signals judged to be normal, and outputs the OR signal to the signal switching circuit 4. To do.

2 out of 3 circuit 2 is composed of three AND circuits 21, 22, 23 and one OR circuit 24, and outputs at least two of the three signals A, B, C when the same signal is output. To do. In other words, even if one of the signals is abnormal, 2out
A normal signal is obtained at the output of the of3 circuit 2.

The differentiating circuit 3 is composed of a capacitor C1 and a diode D1, and differentiates the output signal of the 2out of 3 circuit 2 at the rising time thereof to obtain a narrow signal D.

Differentiating circuits 9A, 9B, 9C are composed of capacitors C2, C3, C4 and diodes D2, D3, D4, respectively, and differentiate the ignition signals A, B, C at their rising points to narrow signals A1, B2, Get C3.

The signal switching circuit 4 normally passes the output of the 2out of 3 circuit 2, and when at least one output of the signals A, B, and C is abnormal, the output of the OR circuit 11 is replaced with the output of the 2out of 3 circuit 2. It is passed through and consists of one inverter 41 and two AND circuits 42 and 43.

Next, the operation of the embodiment shown in FIG. 1 will be described with reference to the time chart shown in FIG. From time t1 to time t2 in FIG. 2, all signals A, B and C are normal. It is assumed that the firing signal C is in an abnormally high level state at time t2, and the determination signal c is in a low level state at time t4. The time between t2 and t4 is the time required for abnormality determination.

Since the determination signals a, b, and c are all in the high level state between t1 and t4, the output of the AND circuit 13 becomes the high level signal. Therefore, a high level signal is given to one input terminal of the AND circuit 42, and an inverter is provided to one input terminal of the AND circuit 43.
A low level signal is provided via 41. Therefore, in this case, the signal switching circuit 4 passes the output of the 2out of 3 circuits, that is, the narrow signal D after passing through the differentiating circuit 3 (shaded pulse D1, D2, D3 in FIG. 2), and the output of the OR circuit 11. Do not pass E. This is because if the output E of the OR circuit 11 is adopted, an erroneous pulse E1 due to the abnormal signal C is output at time t2 before the output of the normal signal E2 at time t3.

Since the determination signal c is in the low level state after time t4, the output of the AND circuit 13 is also in the low level state. Therefore, a low level signal is given to one input terminal of the AND circuit 42,
A high level signal is applied to one input terminal of the AND circuit 43 via the inverter 41. Therefore, in this case, the signal switching circuit 4 does not pass the output of the 2out of 3 circuit, that is, the narrow signal D after passing through the differentiating circuit 3, but passes the output E of the OR circuit 11 (shaded pulse E3 in FIG. 2, E4). This is because if the output of the 2out of 3 circuit is adopted after time t4, for example, if the ignition signal B disappears and fails at time t6, no output is obtained. This point OR circuit 11 has only one normal signal A
Only with this, the normal output E4 can be obtained.

FIG. 3 shows the circuit configuration of the abnormality monitoring device 12, and the AX of FIG.
~ RS shows the waveform of each part.

Thyristor firing signals A, B, C generated by the respective pulse generators are input to differentiating circuits 64, 65, 66. Differentiator 64,
The differentiated signals AX, BX, CX differentiated by 65, 66 are input to the reset flip-flops 61, 62, 63. The output signals of the flip-flops 61, 62, 63 are input to a microcomputer (MPU) 67 to diagnose normal / abnormal conditions. The output D or E of the signal switching circuit 4 is also input to the MPU 67.

Here, the MPU 67 gives a reset signal RS having the same cycle as the normal pulse to be generated by the three pulse generators to the respective flip-flops 61, 62, 63, and after reset, the differential signals AX, BX,
A normal / abnormal state is determined based on the signal level of the output of each flip-flop output in response to the set signal which is CX when the signal from the signal switching circuit 4 is input. Specifically, the MPU 67 receives signals AY, BY, CY at the time of inputting D or E.
Is a high level signal, it is judged to be a normal signal, a low level is judged to be an abnormal signal, and when it is judged to be a normal signal, high level signals a, b and c are output, If it is determined that the low level signals a, b, c are output. In addition, since it is judged whether each pulse generator is normal or abnormal, the reset signal RS
Is generated at the same cycle as the normal pulse of the pulse generator as described above.

The pulse generators 1A, 1B, 1C may be driven based on a normal on / off command or may be driven based on a forward voltage or reverse voltage detection signal of the thyristor.

〔The invention's effect〕

According to the present invention, a highly reliable thyristor ignition circuit can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a diagram showing the waveform of each part of FIGS. 1 and 3, and FIG. 3 is a circuit configuration diagram of the abnormality monitoring device of FIG. 1A, 1B, 1C ... Pulse generator, 2 ... 2 out of 3 circuits, 3 ...
... differential circuit, 4 ... signal switching circuit, 5 ... pulse amplifier, 6 ... light emitting diode, 7 ... light guide, 8 ...
… Thyristor, 9A, 9B, 9C …… Differentiating circuit, 10A, 10B, 10C…
… And circuit, 11 …… or circuit.

Claims (2)

[Claims] 1. Three pulse generators for independently outputting a firing signal of a thyristor, and when at least two outputs out of the three outputs of these pulse generators are the same signal, the same signal is outputted to the thyristor. 2 out of 3 circuits, an abnormality monitoring device for judging normal / abnormal of each output of the pulse generator, an OR circuit for inputting only the normal output of the 3 outputs of the generator in response to a command from the abnormality monitoring device, and the above 3 And a signal switching circuit for providing the output of the OR circuit to the thyristor in place of the output of the 2out of 3 circuit in which at least one of the outputs is determined to be abnormal. Three differentiating circuits that differentiate each output, three flip-flops that use the outputs of these differentiating circuits as set signals, and the normal pulse that should be generated by the above three pulse generators. A reset signal having the same cycle as that of the input signal from the signal switching circuit, which is output in response to the set signal from the differentiating circuit after reset. A thyristor firing circuit comprising: means for judging normal / abnormal based on a signal level at a time point. 2. In claim 1, 2 out of 3
A firing circuit of a thyristor, wherein a differentiating circuit is inserted in each of an output side of the circuit and an input side of the OR circuit.