JPS61150666A - Defect signal transmission system of thyristor - Google Patents

Abstract

PURPOSE:To readily detect a malfunction by connecting light emitting elements having different wavelengths with a plurality of thyristors connected in series with a high voltage circuit, combining the outputs, and transmitting it through an optical fiber at a low potential side to divide to waves. CONSTITUTION:A plurality (3 as shown) of thyristors 11A-11C are connected in series with a high voltage circuit. Resistors 12A-12C and diodes 13A-13C are connected in series with the thyristors 11A-11C, and the first - third light emitting diodes 21-23 which output lights of different wavelengths are connected in parallel with the diodes 13A-13C. The light of diodes are led by light guides 24A-24C to a light composite nit 25 to combine them, and transmitted by a transmitter 36. It is photoelectrically converted by photodiodes 31-33 through light filters 27, compared by comparators 17A-17C, and input to a controller 18. Thus, less light guides are used to detect the malfunction of the thyristor by a circuit insulated from a high voltage circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to a transmission system for transmitting failure signals from a plurality of SI risks connected to a high voltage circuit to a low potential side.

[Prior art and its problems]

FIG. 3 shows a conventional method for transmitting failure signals of multiple thyristors connected to a high voltage circuit. FIG. In this 3rd v, three thyristors II
A, IIB, and IIC are connected in series to the high voltage circuit, and a series circuit of a resistor 12A and a diode 13A is connected in parallel to the Uthyristor IIA, and a light emitting diode 14A is connected in parallel to this diode 13A. Since it is connected, the load/voltage of thyristor IIA is converted into an optical signal. This optical signal is transmitted to a low level (till) via a light guide 15A, which also serves as insulation, and is converted into an electrical signal by a photodiode 16A and a comparator 17A, and input to a control circuit 18. The same applies to thyristors 11B and 1iC. resistance 128, 120
and diode 13B, tac and light emitting diode 14
The burden voltage of each thyristor is converted into an optical signal by the light guides 15B and 14C, and each is separately transmitted to the light guides 15B and 14C.
15C to the low potential side, and the photodiode 16
B, 16c and comparators 17B, 17C convert it into an electrical signal and input it to the 1tl1m circuit 18. If it is detected from the burden voltage that only thyristor IIA is not turned on even though all three thyristors IIA, 11B, and IIC are instructed to turn on, the control circuit 18 IIA determines that it is a failure and takes appropriate measures.

As mentioned above, by using optical signals, the on/off state of the thyristors connected to the high voltage circuit is isolated from the high voltage circuit and transmitted to the low potential side to detect whether or not there is a failure in each thyristor. If so, these devices not only become extremely expensive due to the need to use the same number of expensive light guides as thyristors, but also have the disadvantage of occupying a large space to arrange the light guides. Also have/do.

[Purpose of the invention]

An object of the present invention is to provide a thyristor failure signal transmission system that can transmit failure signals of a plurality of thyristors connected to a high voltage circuit to a low potential side using a small number of light guides.

[Key points of the invention]

This invention encodes failure signals from multiple thyristors connected to a high voltage circuit using light emitting patterns of multiple light emitting elements of different wavelengths, combines these optical signals with an optical multiplexer, and then transmits them to a light guide. This is an attempt to transmit a failure signal to a large number of thyristors using a small number of light guides, by transmitting it to the low potential side and then demultiplexing it using an optical demultiplexer.

[Embodiments of the invention]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention. In this figure, there are three thyristors IIA.

11B and 11C are connected in series, and these thyristors are connected to a high voltage circuit.

A series circuit of a resistor 12A and a diode 13A is connected in parallel to the thyristor IIA, and a first light emitting diode 21 is connected in parallel to the diode 13A. This optical signal is sent to the optical multiplexer δ by the light guide 24A. Similarly, a resistor 12B and a diode 1313 are connected in parallel to the thyristor IIB, and a second light emitting diode 4 that outputs an optical signal with a wavelength of λ2 is connected in parallel to the diode 13B. In addition, a series circuit of a resistor 12C and a diode 13C is connected in parallel to the thyristor 11C, and the third light emitting diode connected in parallel to the diode 13C outputs an optical signal with a wavelength of λ3, so the second light emitting diode n The optical signal from the third light emitting diode and the optical signal from the third light emitting diode are also sent to the optical multiplexer 5 via the light guides 24B and 24C, respectively.

The optical multiplexer 6 receives input λ1. λ2. Since optical signals of three different wavelengths λ3 are combined and output, this combined signal is transmitted to the low potential side using one light guide. An optical demultiplexer n is provided on the low potential side, and demultiplexes the input optical signal into an optical signal with a wavelength of λ1, an optical signal with a wavelength of λ2, and an optical signal with a wavelength of λ3. passes through the light guide 28A to the first photodiode 31
This electric signal is input to comparator 17A to determine the operating state of thyristor IIA. Similarly, the optical signal with the wavelength λ2 output from the optical demultiplexer n passes through the light guide 28B and is converted into an electrical signal by the second photodiode branch and the comparator 17B, and the optical signal with the wavelength λ3 passes through the light guide 28C. It is converted into an electrical signal by the third photodiode and the comparator 17C, but these comparators 17A,
17B.

The '11 signals output from 17C indicate the operating states of thyristors IIA, IIB, and IIC, so these electric signals are input to the control circuit 18 and compared with the gate command signal of each thyristor. Method ζThyristors IIA, IIB, II
It is detected whether or not C is operating as instructed, that is, whether or not there is a failure in the thyristor.

FIG. 2 is a diagram showing a second embodiment of the present invention. In this FIG. 2, three thyristors IIA,
IIB and IIC are connected in series, and these thyristors are connected to a high voltage circuit. A series circuit of resistor 12A and diode 13A is connected in parallel to thyristor IIA, and similarly a series circuit of resistor 12B and diode 13B and a series circuit of resistor 12c and diode 13C are connected in parallel to thyristors IIB and 11C, respectively. This is the same as in the embodiment shown in FIG. 1 described above.

In the second embodiment shown in FIG. 2, an encoder 41 and a decoder 46 are provided. i.e. diode 1
By separately introducing the terminal voltage of 3A, the terminal voltage of the diode 13i3, and the terminal voltage of the diode 13c to the encoder 41, the thyristors 11A, IIB.

Since the state of 11C is converted into a corresponding binary axis word, the output of this encoder 41 is guided to a light emitting device 42 having a plurality of light emitting elements with different wavelengths, and the output light 16 of different improvements is output from the light emitting device 42. As mentioned above, the signals are multiplexed by the optical multiplexer 6. The scene is the same as in Figure 1. This multiplexed optical signal is transmitted to the low potential side by the 2-wavelength filter which also serves as an insulator, and the optical signal demultiplexed for each wavelength by the optical demultiplexer 27 is converted into an electrical signal by the light receiving device 45. The signal is converted into a signal, further decoded by the decoder 46, and then input to the control circuit [18].

By using the encoder 41 and the decoder molding in this manner, 2n codes can be transmitted from the high voltage side to the low potential side with one light guide by using a light emitting element with a wavelength of n[ti. In other words, even if the FM length of the light used is the same, the fruit 2) i! More thyristor failure signals can be transmitted with the same number of light guides as in the example.

〔Effect of the invention〕

According to this invention, the failure signals of a plurality of thyristors connected to a high voltage circuit are converted into optical signals by light emitting elements of different wavelengths, the same number as the number of thyristors, or the failure signals of a tin risk are converted into optical signals. It is converted into an optical signal via an encoder using light emitting elements with different wavelengths, which number is smaller than the number of thyristors, and these multiple optical signals are combined and transmitted to the low potential side using a small number of light guides. Therefore, even if a large number of thyristors are connected to a high-voltage circuit, the failure signal of each thyristor can be transmitted with a small number of light guides, which can significantly reduce the cost and reduce the number of light guides with 6 light guides. It also has the effect of significantly reducing shoulder space.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, and FIG.
The figure is a block diagram showing an example of the second #NN of the present invention. FIG. 3 is a circuit configuration diagram showing a conventional method for transmitting failure signals of a plurality of thyristors connected to a high voltage circuit. tlA, tIB, 1tc...thyristor, 12A,
12B, 12C...Resistance, 13A, 13B
, 13C...diode, 14A, 14B
, 14C...Light emitting diode, 15A, 15B
, 15C...Light guide, 16A, 16B
, 16c... photodiode, 17A, 17
B, 17C... Comparator, 18... Control circuit, 21... First light emitting diode, ρ... Second light emitting diode, n... Third light emitting diode, 24A, 2
4B, 24C... Light guide, 25... Optical multiplexer, G... Light guide, n... Optical demultiplexer, 28A,
28B, 28C...Light guide, 31...First photodiode, Proverbs...Second photodiode, Ah...
Third photodiode, 41... Encoder, 42...
- Light emitting device, TS... Light receiving device, 46... Decoder.

Claims (1)

[Claims] When a plurality of thyristors are connected in series and connected to a high voltage circuit, the presence or absence of a thyristor failure is detected from the burden voltage of each thyristor. A thyristor failure signal transmission method that is coded by a pattern, multiplexes light with different wavelengths, transmits it to the low potential side, and then splits the light.