SU1647798A1 - Device for turning on thyristor - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to increase efficiency and reliability. For this purpose, the device contains a power 1 and auxiliary 12 thyristors, two capacitors 6.10, two resistors 7.9, three diodes 8, 11, 13, a control switch 5, and a threshold element 14. Auxiliary thyristor 12 opens in negative half-cycle the current of the first capacitor 6, then at the beginning of the positive half-cycle the recharge current of the second capacitor 10 opens the power thyristor 1. The energy stored in the second capacitor 10 recovers to the network when recharged, the resistors 7.9 limit the current surges into the condensate rah 6.10 to acceptable and losses are small. 2 hp ff, 2 ill.

Description

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The invention relates to electrical engineering and can be used to control power thyristors with a load connected once at the beginning of the positive half-cycle of the supply voltage.

The purpose of the invention is to increase reliability by simplifying and increasing efficiency. FIG. 1 and 2 shows a diagram of the device options

The device (Fig. 1) for turning on the power thyristor 1, the cathode of which is connected to the first output of network 2, and the anode is connected to the first output of load 3, the second output of which is connected to the output of network 4, contains a control switch 5, the common output of which is connected to the first terminal of the first capacitor 6, the second terminal of which is connected to the first terminal of the first resistor 7, the second terminal of the latter is connected to the anode of the first diode 8, to the disconnecting contact of switch 5 and the network terminal 2. The control electrode of circuit 1 is connected to the cathode diode and 8 and the first output of the second resistor 9, the second output of which is connected to the first output of the second capacitor 10, the second output of the latter with the cathode of the second dmod 11 and the anode of the auxiliary thyristor 12, the cathode of the latter and the anode of the diode 11 are connected to the output of the network 4, the make contact of the switch 5 connected to the anode of the third diode 13, the cathode of which is connected to the first output of the threshold element 14, the second output of which is connected to the control electrode of the thyristor 12.

A fourth diode 15 can be inserted into the device (FIG. 2) and the break contact of the switch is connected to the control, the thyristor 1 electrode.

The device works as follows.

In the initial position, capacitor 6 is discharged through resistor 7 and contact of switch 5, and capacitor 10 is charged to a positive voltage equal to the amplitude of the supply voltage through diode 11, resistor 9 and the control electrode of the thyristor 1.

When switching the switch 5 to the negative half-period, after the network voltage exceeds the threshold of the element 14, the capacitor 6 starts charging from pin 2 through the resistor 7, the switch 5 contact, diode 13, element 14 and the thyristor control electrode 12. The latter opens and the capacitor 10 starts recharge under the influence of the voltage on it and the network. At the beginning of the positive half cycle, the current through the capacitor flows from

pin 4 through the diode 11 to the control electrode of the thyristor 1.

The thyristor 1 opens by applying voltage to the load 3. Next, the capacitor 10 is charged to a positive amplitude value of the supply voltage, the current in it disappears, and the thyristor 1 closes at the end of the positive half period. The circuit is in steady state, in which thyristors 1 and 12 are locked, and capacitors 6 and 10 are charged.

The circuit returns to its initial position when the switch 5 is switched to the position where the capacitor 6 discharges 5 through the resistor 1. The new one-time switching on of the thyristor 1 will be at the closure of the charge circuit of the capacitor 6 by the switch 5.

The threshold element 14 makes it impossible to start the charge of the capacitor 6 in the greater part of the second half of the negative half-period, for which its threshold is chosen approaching the amplitude of the network voltage.

5 In the case of the element 14 being a threshold key (for example, in the form of a diode thyristor), the unlocking of the thyristor 12 is possible near the middle of the negative half-period of the mains voltage only 0 with a jump in the charge current of the capacitor b, and therefore the resistance value of the resistor 7 is determined only by the maximum permissible currents in the chain from the resistor 7 to the control electrode of the thyristor 12. 5 The circuit (FIG. 2) does not have a single turn on of the thyristor 1 when voltage is applied to it, since the capacitor 10 is charged in the positive half period com, passing through the switch 5 0 and diode 15. In the working position when charging the capacitor b circuits (Figures 1 and 2) are the same, After the thyristor 1 opens, returning the switch to its initial position causes the capacitor 6 to open through re - 5 resistor 7 and diode 8.

Claims (3)

Claim 1. Device for switching on a thyristor connected in series with the load to the mains leads, containing 0 in series. the first diode, the first resistor, the first capacitor and the common output of the switch, the disconnecting contact of which is connected to one of the terminals of the first diode, connected in series 5 to the second capacitor, the second resistor and the second diode, auxiliary thyristor, the cathode of which is connected In order to increase efficiency and reliability, a series-connected threshold element and a third diode, the anode of which is connected to the closing contact of the switch, and the free output the auxiliary thyristor, the anode of which is connected to the junction point of the second diode and the second capacitor; the cathode of the auxiliary thyristor is connected to the anode of the second diode and is intended to be connected to the free output terminal; the anode of the first diode is connected to connection to the manager FIG. 2 0 the electrode of which is intended the cathode of the first diode and the free output of the second resistor. 2. The device is pop. 1. Distinguishing with the fact that a fourth diode is inserted, the anode of which is connected to the common output of the switch, the cathode is connected to the anode of the first diode, and the break contact of the switch is connected to the cathode of the first diode. 3. Pop 1 device, characterized in that a key threshold element is used as a threshold element.