SU964962A1 - Device for control of cycle converter - Google Patents

Description

one

The invention relates to a converter technique and is intended to control thyristor H1, 1 mi cycloconverters.

A device for controlling a converter is known, comprising a master oscillator, a scaler, pulse shapers with modulators and demodulators, and output transformers (1.

The disadvantage of the device is complexity.

Closest to the invention is a cycloconverter control device which comprises a low frequency sensor, a scaler, a high frequency sensor, a mixer, output keys. The output of the low frequency sensor is connected to the input of recalculated | unit, the conversion unit - with a mixer, the mixer - with the output valves, and the output of the sensor frequency sensor - with a mixer. A low frequency sensor sets the frequency of the output voltage of the converter, the shift between the phases of which determines the scaler. The high frequency sensor includes a phase shifting device and a shaper of high frequency pulses, common mode and synchronic: with the frequency of the mains voltage. In the mixer, the output frequency pulses and the frequency pulses of the supply network are mixed in such a way that packets are output from the mixer outputs to the output switches, which are then amplified and fed to the control electrodes of the thyristors {2.

However, such a device does not provide transition and operation of the converter in the mode

10 when its output frequency is equal to the mains voltage frequency (switch mode), since there is no phase synchronization of the scaling unit with the network of the source of the inverter's pahty. In addition, not all the thyristors of the converter work in the switch mode, therefore, for uniform thermal loading of the power thyristors, it is not necessary to switch on a new group of gates from each frequency conversion mode to the switch mode for each new transfer of the transducer elements.

I The purpose of the invention is to expand the functional capabilities of the converter by ensuring its operation in the switch mode, as well as increasing its reliability, by periodically changing the groups of tyrsthors providing this mode.

The goal is achieved by the fact that the device is additionally equipped with a mode switch, an annular shift register with a pulse selection unit, a decoder and three BAN elements, the pulse generator being connected to the input of the scaling unit through the first BAN element, the high frequency sensor is connected to the synchronizing input of the pulse through the pulse selection unit the block, and through the second element BAN - with the input of the counting block, the mode switch is connected to the three BAN elements and to the ring shift register, tory via a third element connected to the inverted pulse selecting unit and a decoder connected to the mixer.

FIG. 1 shows a diagram of the proposed device; in fig. 2 - cycloconverter circuit; in fig. 3 - time diagrams.

The low frequency sensor 1 is connected through the BANNER element 2 to the input of the scaling unit 3. The output of the scaling unit is connected to the mixer 4, which is connected to the output keys 5. The high frequency sensor 6 is connected to the synchronizing input of the scaling unit 3 via the pulse selector unit 7 and the second the BANCH element 8 is connected to another input of the conversion unit 3, mode switch 9 is connected to three BANTS 2, 8 and 10 elements and to the annular shift register 11, which, in turn, is connected to the block selector 10 Pulse 7 and decoder 12 connected to the mixer 4.

The cycloconverter is made on thyristors 13-30;

Mode switch 9 determines the operation of the cycloconverter either in the frequency conversion mode or in the switch mode.

The ring shift register 11, with each new transition of the frequency converter to switch mode, changes the state of its outputs (a single potential is transferred from one output to another). The number of triggers of the shift resistor is equal to the number of power thyristor groups, each of which includes the minimum number of thyristors sufficient to provide the switch mode of the converter.

The ring shift register 11 through the element BAN 10, which has the number of cells.

equal to the number of outputs of the ring shift register 11, controls the operation of the pulse selection unit 7 and the decoder 12. The signals from the outputs of the decoder 12 enter the mixer 4, where the control pulses are allowed to pass to the thyristors selected to provide the switching mode and block the control channels of the other thyristors.

The pulse selection unit 7 includes a set of BANKS cells, the number of which is equal to the number of phases of the cyclo-converter voltage supply. Through the first inputs of the BANGE cells, they are controlled by the output signals of the ring shift register, and the second inputs from the high frequency sensor 6 receive voltage pulses with a frequency equal to the supply voltage, synchronous and in-phase with it, and pulses are sent to each BANNER cell, phased with a strictly defined phase of the voltage supplying cycloconverter. These pulses through the cell BANKS of the pulse selection block 7 are fed to the synchronization input of the counting block- 3.

In addition to the pulses for synchronization of the scaling unit 3, the high frequency sensor 6 produces high-frequency pulses of the voltage U synchronized and phased with a supply voltage whose frequency is equal to

ffiM-l f

WITH

where fo is the frequency of the supply voltage; k - division factor

block 3.

In the frequency conversion mode, the output frequency of the converter is determined by a pulse generator, the output pulses of which, at the command of mode switch 9, are transmitted through the element BANGE 2 to the input of counting unit 3. When the converter is switched to switch mode, the mode switch -9 prevents the pulse of the geyrator pulse from passing through the BAN 8 element. the input of the counting unit 3, from the output of the high frequency sensor 6 receives high-frequency pulses Up. The output frequency of the transducer becomes

equal to vhrd11oy. At the same time, through the BANNER element 10, the outputs of the ring shift register 11 are connected to the inputs of the pulse selector 7 and the decoder 12. Depending on the state of the outputs of the ring shift register AND the decoder 12, a certain group of thyristors is selected for switch mode operation, and the pulse selection block 7 is selected for synchronization 156 of the scaling unit 3 selects those pulses from the U high-frequency sensor 6, which are phased with a specific phase of the supply voltage converter in accordance with the selected decryptor thyristors. When the cycloconverter returns to the direct frequency conversion mode, its output frequency is determined by a low frequency sensor (VLF). Prohibiting element 10 by the command of mode switch 9 prohibits the operation of the pulse selection unit 7 and the decoder 12. The output signals of the decoder 12 allow the operation of all the thyristors of the converter . Switching the command mode to the new transition of the converter to the switch mode results in connecting the output of the high-frequency pulse generator of the high-frequency sensor 6 to the input of counting unit 3, as well as changing the output state of the 1G ring register and connecting them to the inputs of the decoder pulse selector 12 This leads to the fact that the decoder height ,, f, p.,., .. “... takes another group of thyristors for operation, and the synchronization of the conversion unit comes from pulses phased from another phase supplying go voltage converter. Thus, with each new transition of the frequency converter to the switch mode, the device ensures the selection of a new group of thyristors and the corresponding synchronization of the scaling unit. After successive participation in the work of all thyristor groups, the next transition to switch mode, the first group enters again, and so on. Consider the operation of the device on the example of a three-phase-three-phase 18-valve cycloconverter. Since it is enough to have six thyristors in operation to provide the switch mode, the power part of the driver can be divided into three groups, each of which can provide the switch mode: Group I - thyristors, 13,16,20,23,27,30; Group II - thyristors 14,17,24,25,28; Group III - thyristors 15,18,19,22,26,29. With the same order of alternation of the output phases of the converter (Fig. 2), each phase of the motor in three cases is connected with thyristors. to different phases of the net-, melting network. Therefore, the operation of the conversion unit in each case must be synchronized with respect to a particular phase of the network. Timing diagrams explain the principle of synchronization of the scaling unit 6 with its division factor to 6. The phase voltages of the network are denoted by the following: U - high frequency pulses of the high frequency sensor 6 (Fig. 1), in-phase with the daughters of natural thyristor ignition and having a frequency of -tc-UilJ lU j. btj ,,, - С С high frequency sensor pulse pulses, - having a frequency equal to the input and in-phase with the natural ignition points of thyristors of individual network phases, and these pulses correspond to negative voltages of m thyristors: Q, 0 (,., - output signals recalculated block 3 (Fig. 1). In this case, Q, Q - form the output voltage of the cycloconverter phase; Fzzy (3j, Qj are phases C, respectively. If decoder 12 selects the first group for operation in switch mode, thyristors, then. synchronization the scaling unit 3 is carried out by a pulse and a. i, which are selected by the block CD gm of the selection of pulses 7. When these pulses are received at the synchronizing input of the scaling unit 3 (moments tj, tj, tj), the triggers of the scaling unit 7 are set to , starting with the arrival at the input of the counting unit of the next high-frequency pulse and (time tj), at the outputs Q ,,, Q of the counting unit 3, rectangular pulses are formed with phase phase and with the supply voltage of the input phase a, at the outputs of the supply voltage phase in it, on February 11 outputs phase. These pulses enter the mixer to form the output voltage of the converter at a frequency equal to the network frequency. When the cycloconverter is in operation, when the switch mode provides the second group of thyristors to maintain the order of alternation of the output phases, the output phase A of the converter is connected to the input phase b by the thyristors 14 and 17, the output phase B using the thyristors 21 and 24 to the input phase c, and the output phase phase C thyristors 25 and 28 is connected to the input phase a. In this case, the block for selecting pulses 7 (Fig. 1) selects the pulses U (P (times ts, ta, tj).) Now, starting from time tj, at the outputs. Q-), Q - recalculated. block, rectangular pulses are formed, in-phase with the input voltage

the outputs u i Qi - with the power supply voltage of the input phase c, at the outputs of the phase a.

When the third group is operating, the output phase A of the converter is connected to the input phase c, phase B to input a, phase C to the input phase c. Impulses f with | corresponding synchronization of the conversion unit 3 is performed.

Thus, the proposed cycloconverter control device provides a three-phase voltage at the output of the converter with a mains frequency, as well as a periodic circuit of the thyristor groups providing this mode.

Claims (2)

1. USSR Author's Certificate No. 217515, class H 02 R 13/30, 19i68. 2. USSR author's certificate N 213166, cl. H 02 R 13/30, 1969. Ua iuUt fS (/ c