SU1003268A1 - Control pulse distributing device - Google Patents

Description

The invention relates to electrical engineering and can be used as part of a single-channel control system for a three-phase rectifier, consisting of two three-phase thyristor bridges connected in parallel, for example, through 5 equalization reactors.

Three-phase voltage systems supplying these bridges are phase shifted relative to each other by 30 e. hail., due to which the output voltage ^{from the} rectifier contains 12 ripples in the period of the supply network, which ensures a low level of ripple.

To control such a rectifier, it is necessary to develop two sets of ^1: six pulse sequences, 120 ° wide, and in each sequence relative to the adjacent pulses should be shifted by 60 °, and ₂ pulses in one of the sets relative to the corresponding pulses in the other set - by 30 °. In order to reduce control losses and simplify the output devices of the bridge rectifier control system, while maintaining its stable operation in the intermittent current mode, it is advisable to replace the wide control pulses with double narrow pulses with a duration of about 3 °, and the second should follow the first after 60 °.

A device for distributing control pulses is known, which contains a ring circuit on triggers with circuits providing fault correction. It generates m sequences of pulses following through 27Ϊ / t degrees and having the same width [1].

When a three-phase bridge rectifier with this control operates, intermittent current mode will cause significant malfunctions, or even a complete cessation of operation.

The closest in technical essence to the proposed one is a device for distributing control pulses containing a sequential six-digit shift register

£) -triggers [2J.

'The disadvantage of this device is the inability to generate dual. narrow pulses required for controlled ₅ Lenia-phase double-bridge rectifier.

The purpose of the invention is the expansion of the functionality of the device.

To achieve the set goal _{t0, the} device is equipped with a single vibrator, a counting trigger, two 2 AND elements, an 3 OR-NOT element and two output units, each of which consists of six two-input combining elements, the inputs of the one-shot and the counting trigger connected to the device input, the trigger outputs - in pairs to the first inputs of two elements; 2 And ,; the second inputs of which are connected to the output of the one-shot, the first inputs of the matching elements of both output blocks are paired, connected to the outputs of two elements 2 AND, the second inputs - with the outputs of the corresponding bits of the register, 25 outputs of the second, third and fourth bits through element 3 OR- HE are connected to the input of the first digit, and the clock input of the register is connected to the output of the counting trigger.

In FIG. 1 shows a functional diagram of a device; in FIG. 2 - time diagrams explaining his work.

A device for distributing control pulses contains six D-triggers 1-6, combined into a shift register 7, a single vibrator 8 and a counting trigger 9, the inputs of which are connected to the input of the device, the outputs of the counting trigger are paired to the first inputs of two elements 2 AND 10 and 11, the second inputs of which are connected to the output of the one-shot, two output blocks 12 and 13, each of which contains six coincidence elements 14, the first inputs of which ⁴⁵ are paired with the outputs of two elements 2 And, and the second inputs with the outputs of the corresponding register bits. The outputs of the triggers of the second, third and fourth digits of the register through the element 3 OR NOT 15 are connected to the D-input of the trigger of the first category.

The device operates as follows. 55

Counting trigger 9 divides the clock frequency (frequency _input pulses, ϋβχ) in half. Signal b. coming from the inverted output of trigger 9, with its trailing edge, shifts the contents of register 7 to the right. Due to the presence of feedback through element 3, OR NOT 15, this content is one of the words: moreover, this feedback ensures the restoration of one of these states after a failure is not (Later, after 4 cycles.

The status of any of the 12 outputs of the device is determined by the expression

U-ΐκ ~ θη i where, ί = 1,2; K = 1.6, with _ υ _η1 = δηυ _0Β ,

Since the states of the trigger 9 change after 1/12 of the period T, the identical * states of the output blocks 12 and 13 follow each other through 30 electric degrees, moreover, at each beat in turn in each of the output blocks 12 or 13 alternately control pulses are formed at two adjacent outputs, the duration of which is equal to the duration of the output pulses of the single-shot 8 and which provide control of the two-bridge rectifier.

Claims (2)

(54) DEVICE FOR DISTRIBUTION OF CONTROL PULSES The invention relates to electrical engineering and can be used as part of a single-channel control system for a three-phase expander, consisting of two three-phase thyristor bridges connected in parallel, for example, through equalization reactors. The three-phase voltage systems supplying these bridges are phase shifted relative to each other by 30 el. grad., thanks to which the output voltage of the thrust system contains 12 pulsations in the period of the supply network, which ensures a low level of pulsations. To control such an exponent, it is necessary to generate two sets of six sequences of pulses with a width, and in each sequence relative to the neighboring impulses must be shifted by 60 °, and the pulses in one of the sets relative to their corresponding pulses in the other set - by 30 °. In order to reduce the control losses and simplify the output devices of the bridge control system, while maintaining a stable operation in the stall current mode, it is advisable to replace the wide control pulses with double narrow ones, of the order of 3 °, the second should follow the first after 60 ° A device for distributing control pulses is known, which comprises an annular circuit on triggers with chains that provide for the correction of faults. It generates m sequences of pulses, following through 2L / t degrees and having the same width of 113. During the operation of a three-phase bridge rectifier with such control in the discontinuous current mode, there will be significant failures, or even a complete cessation of work. The closest in technical terms to the proposed device is a device for the distribution of control pulses, which contains a sequential six bit $ 1d shift register on P-transactors 2 3. A disadvantage of this device is the impossibility of generating double narrow pulses necessary for controlling a three phase two bridge head. The purpose of the invention is to expand the functionality of the device. To achieve the delivered delta, the device is equipped with a one-shot, counting trigger, two elements 2 AND, element 3 OR-NOT and two output blocks, each of which is I of six two-input elements of common, and the inputs of the one-shot and counting trigger are connected to the input devices, trigger outputs - nonagjio to the first inputs of two elements; 2 Hj the second inputs of which are connected to the output of the single vibrator, the first inputs of the matching elements of both output blocks in pairs, are connected to the outputs of the two elements 2 And the second inputs with the outputs of the corresponding bits of the register outputs of the second, third and quarter bits through the element 3 OR-NOT are connected to the input of the first bit, and the register input is connected to the output of the counting trigger. FIG. 1 shows a functional diagram of the device; in fig. 2 - time diagrams, which show his work. The device for distributing control pulses contains six D-triggers 1-6, combined into a shift register 7, a single vibrator 8 and a counting trigger 9, whose inputs are connected to the input of the device, the outputs of a counting trigger, pairwise to the first inputs of two elements 2 10 and 11, the second inputs of which are connected to the single-output output, two output blocks 12 and 13, each of which contains six coincidence elements 14, the first inputs of which are pairwise connected to the codes of the two elements 2 And Dov register. The outputs of the second, third, and fourth register triggers through the element 3 OR-NOT 15 are connected to the D input of the first bit trigger. The device works as follows. The counting trigger O divides the clock frequency (the frequency of the input pulses Ugj; in half. The signal R coming from the inverse output of the trigger 9, with its back edge, shifts the content of the register 7 to the right. Thanks to the feedback from element 3 OR-NOT 15 this The content is one of the words: 110000, 0110OO, 001100, 000110, 000011, 10OOO1, and the specified feedback ensures that one of these conditions is restored after no more than 4 takha. expression, -Pack where 1.2; K 1.6; moreover, Un. "RiUoB. Since the states of the trigger 9 change after 1/12 of the period T, then the same states of the output blocks 12 and 13 follow each other through 30 el. hail. In each cycle, in each output block 12 or 13 alternately, control pulses are formed alternately on two adjacent outputs, the duration of which is equal to the duration of the output pulses of the one-shot 8 and which control the two-bridge rectifier. Claims An apparatus for distributing control pulses of a single-channel three-phase supervisory control system, comprising a sequential dividing shift register on D triggers, characterized in that, in order to expand the functional capabilities, it is equipped with a single vibrator, a counting trigger, two 2 AND elements , element 3 OR-NOT and two output blocks, each of which consists of six two-input coincidence elements, with the inputs of the one-shot and counting trigger connected ji device input The outputs of the trigger are pairwise to the first inputs of two elements 2 And, the second inputs of which are connected to the output of the one-shot, the first inputs of the elements of coincidence of both output blocks are pairwise connected to the outputs of two elements 2 And, the second inputs to the outputs of the corresponding register bits, the second , the third and fourth bits through the element 3 OR are NOT connected to the input of the first bit, and the clock input of the register is connected to the output of the counting trigger. 51003268 " Information sources, 2. Bizikov V. A. and others. Systems taken into account in the examination of thyristor transducer control1. Author's certificate of the USSR frequency. M., Eiergoizdat 1981 No. 515241, cl. H 02 R 13/16, 1976.s. 82