SU1674303A1 - Device for controlling polyphase converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in electric drives. The purpose of the invention is to simplify the device, increase reliability and manufacturability. To this end, the rectifiers 13 and 14 form the DC voltage used at the terminals of the secondary windings 16 and 17 of the phase transformer 18 as a control voltage for the thyristor converter. Control pulses are generated using photodetectors 8 and 9 of optocouplers 4 and 5 included in the thyristor control circuits. Light emitters 2 and 3 of these optocouplers are included in the output circuits of phase control unit 1. To eliminate the reverse voltages, diode groups 12 and 15 were applied to the photodetectors 9. 2 Cp f-ly, 2 ill.

Description

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WITH

The invention relates to electrical engineering, namely, converter control devices, and can be used in electric drives.

The purpose of the invention is to simplify the device and increase reliability and manufacturability.

FIG. 1 shows a circuit diagram of the device; in fig. 2 - diagrams illustrating the operation of the device.

The device contains a phase control unit 1, the outputs of which are connected to one output of the light emitters 2 and 3 of the respective optocouples of the first 4 and second 5 groups, the other outputs of which are connected to the constant voltage source 6 via a resistor 7, one output of the photodetectors 8 and 9 of the optocoupler of the first 4 and the second 5, respectively, of the groups are designed to be connected to control electrodes.

cathode thyristors 10 and anode 11 respectively groups of the converter. Other conclusions of photodetectors 8 and 9 of optocouplers of the first group 4 are directly, and the second 5 groups through the corresponding diodes of the first 12 group are connected to the positive conclusions of the stabilized rectifiers 13 and 14, respectively. The negative terminal of the rectifier 13 is connected to the cathodes of the thyristors of the cathode group 10, and the negative terminal rectifiers 14 through the corresponding diodes of the second 15 group - with the cathodes of the thyristors of the anode 11 group. The rectifier inputs 13 and 14 are connected to the terminals of the secondary windings 16 and 17 of the phase transformer 18. The secondary winding 19 of which is connected to the clock inputs of unit 1, and the primary winding 20 to the supply network. If necessary, the third 21 group of opto &

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pairs, light emitters 22 of which are installed between the outputs of block 1 and light emitters 3, and photodetectors 23 - between the cathodes of the thyristors of group 11 and the diodes of group 15.

The device works as follows.

Phase voltages are applied to the power part of the converter. When powered from a three-phase industrial network, the time shift between phase voltages is 2 l / 3 - 120 °, i.e. 6.6 ms, f 50 Hz, T 20 ms. When powered from a six-phase industrial network, the time shift between phase voltages is 2/6–60 °, i.e. 3.3 ms FIG. 2 the number of phases m 3.

The phase control unit consists of 2 t of pulse shapers and 2 t of output transistor switches. Suppose that the first positive half-wave of the supply voltage appeared at the UL phase. The pulse shaper of this phase at a certain moment, which depends on what voltage is required at the output of the converter, turns on its output transistor switch. In this case, the circuit: the plus bus of the power source 6, the resistor 7, the light emitter 2, the output transistor switch of the unit 1 - current begins to flow. The current flowing through the light emitter 2 causes the photodetector 8 to open. A positive voltage of Uynpio appears on the control electrode of the corresponding thyristor of the cathode group 10 relative to the cathode of this thyristor. Group 10 thyristor is included. The control pulse duration (opening time of the photodetector 8) is tynp tnwn 10 °, i.e. 0.6 ms This time is enough to fully turn on the thyristor, since a current that exceeds the holding current already flows through the thyristor j when the control voltage is removed. Therefore, the thyristor is turned on. Further, when a positive phase voltage U2 occurs at a certain point in time, the pulse shaper of this phase turns on its output transistor switch and everything repeats. This is how the cathode group 10 works. Similarly, the anode group 11 works, only the Uynp.li impulses are generated when negative half-waves of the power voltage of the phases occur.

Since, in particular, in electric direct current drives, bridge and zero circuits are used with power from an industrial network, the control pulses arriving at the thyristors of the cathode 10 and the anodic 11 groups are always shifted relative to each other. In the anode group 11, due to the fact that the cathodes are separated, optocouplers 21 are used.

The use of such a thyristor switching circuit makes it possible to eliminate pulse transformers, thereby improving the manufacturability and simplifying the device.

Resistor 7 is current limiting. Diode groups 12 and 15 are used to eliminate reverse voltages in the secondary circuits of the optocoupler pairs of groups 5 and 21.

Claims (2)

1. A device for controlling a multiphase converter, comprising a thyristor phase control unit of a converter, the clock inputs of which are connected to the secondary windings of the phase transformer, the primary windings of which are intended to be connected to the mains supply, a constant voltage source, two diode groups and a resistor, characterized in that, in order to simplify the device, increase reliability and manufacturability, two stabilized rectifiers and two groups of optocouplers are introduced, and the phased three-phase transformer is equipped with two additional secondary windings, with the inputs of the first and second stabilized rectifiers connected to the terminals of the first and second additional windings, the positive output of the first stabilized rectifier through the corresponding photodetectors of the first group optocouplers is intended for connection to the control electrodes of the thyristors of the cathode converter group, for connecting to the cathodes of which the negative output of the first stabilized rectifier is intended, the positive output the second stabilized rectifier is connected to the anodes of the diodes of the first group, the cathodes of which through the corresponding photodetectors of the optocouplers of the second group are intended to be connected to the control electrodes of the thyristors of the anode group of the converter, to connect to the cathodes of which the anodes of the second group are intended; of a stabilized rectifier, some of the light emitters of the optocouplers are connected to one output of the resistor, and the other conclusions are connected to the corresponding outputs of the converter's thyristor phase control unit, another output of the resistor connected to the positive terminal of a constant voltage source, 2. The device according to claim 1, characterized in that the other outputs of the light emitters of the optocouplers of the second group are connected to the corresponding outputs of the phase control unit of the thyristors of the converter through the light emitters of the optocouplers of the third group, and the anodes of the diodes of the second group  2, four YU i-l , l-i- al .mc1 x y z№№c2h2 2 22} G T , rc cr с с ч j: Ј {g Ј Ј | dep They are intended for connection to the cathodes of the thyristors of the anode group of the converter through the corresponding photodetectors of the optocouplers of the third circuit. 3 Device on PP. 1 and 2, characterized in that the additional secondary windings of the phase three-phase transformer are six-phase. t h p give 23, M / J W