SU610304A1 - Arrangement for checking-out the operating state of parallel-connected thyristors - Google Patents

Description

The invention relates to control devices in parallel and series-parallel controlled control valves. A device for controlling valves is known, which contains sensors of valve status connected through a logic circuit to the output organ l. The disadvantage of this device is the installation of a separate starting organ on each valve. The closest to the invention in technical essence and achievable results is a control device of parallel-connected circuits containing current sensors of these circuits and a total current sensor connected via a coincidence circuit to the output organ 2j. The disadvantages of this device are the large weight and size. In order to reduce weight and dimensions, the proposed device is equipped with a resistor and a voltage sensor, state sensors are made on optoons whose LEDs are connected between control electrodes and thyristor cathodes through the emitter-collector junction of the transistor, photoresistors are connected in series with each other, and the base of the transistor is connected with voltage sensor. The drawing is a schematic diagram of the device. The device contains a sensor 1 of the state of the thyristors of controlled thyristors 2 and 3 connected via logic 4 to the output organ 5, the sensors 1 of the state of the thyristors are made in the form of LEDs 6 connected by anodes to the control electrodes 7 of the thyristors 2 and 3. The cathodes of the LEDs 6 are turned on parallel to each other and through the trimmer resistor 8 is connected to the emitter of the transistor 9, the collector of which is connected to the common thyristor cathodes. During ignition, LEDs 6 act on photodetectors-photodiodes 10, which are interconnected in series and form a logic circuit. And photodiodes 10 are connected to a DC bus 11 and an amplifier 12, the output of which is connected to one of the inputs of logic circuit 4. On the base of transistor 9 a resistor 13 is connected, which through diode-resistor circuits 14 and 15 is connected to the control electrodes of the thyristors. The voltage sensor 16 forms a pulse that opens the transistor.

9 with a negative half-wave at an AC voltage of 17. The thyristors connected by anodes to the AC bus 18 are connected to the load 19, in series with which the total current sensor 20 is installed, the output of which is connected to another input of logic circuit 4, and its output is connected to the output delay circuit 21 of the output organ 5. Protective RC - chains of thyristors 2 and 3 are not shown in the drawing.

With a positive half-wave on the supply bus 18, transistor 9 opens, but the control current of thyristors 2 and 3 does not flow through it, since both thyristors are locked. When the control pulses arrive at the control electrodes 7, a current flows through the thyristor control circuit, and the transistor 9 is blocked through the diode-resistor circuits.

After the control pulses disappear and the thyristors 2 and 3 open, both the load 19 and the current sensor 20, as well as the LEDs 6, the resistor 8 and the transistor 9 flow current. The LEDs 6 light up and the resistance of the photodiodes 10 decreases sharply. At the output of amplifier 12 and current sensor 20, almost simultaneously, equivalent signals appear at the inputs of circuit 4, at the output of which there is no signal.

When the thyristor 3 is broken with a current circuit (the device works similarly and in the absence of control pulses), transistor 9 opens, thyristor 2 transmits current through load 19 and current sensor 20, at the output of which a signal appears. The thyristor 3 does not conduct current, and therefore, no current flows through the LED 6 of this thyristor. The output of amplifier 12 is the signal O. The signals at the inputs of the circuit 4 are np-equivalent, which causes the appearance

on her way out which

signal

enters the output body 5. Visually by the absence of one ignition

g out of the LEDs 6 is the out of order thyristor 3.

Another type of malfunction is the short circuit failure of a thyristor. In this case, with a negative half-wave on the power bus, through the thyristor 3, the load and the current sensor flow current. At the output of current sensor 20, a signal 1 appears at a signal O at the output of amplitude l 12.

Claims (2)

1 .. Semiconductor rectifiers 4U, ed. F.I. Kovaleva and GoP.Mostkovoy M., Energie, 1967, p. 355, fig. 7-18. 2. Patented. T Germany 1.20-377, 1966, 21 with 68/50.