SU1575280A1 - Device for controlling thyristor converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in thyristor converter control systems. The purpose of the invention is to improve the accuracy of the thyristor converter with changes in the parameters of the power supply voltage. The device contains a source 35 of the control on the yarn, three control channels 1-3 and in each channel - synchronizer 7 (8.9), trigger 13 (14.25), zero - body 16 (17.1 8), counter 20 (21,22), multiplying the digital-to-analog converter 23 (24,25), comparator 29 (31,33), two elements AND 36, 37 (38-41) and two formers 42,43 (44-47) output pulses, generator 19 with a phase locked loop, the output of which is connected to the counting inputs of counters 20-22 of each channel, and the signal input is connected to the inverse output of the third channel trigger 15, the comparator input is connected to output c the highest bit of the counter 15 of the third channel. A shaper 10 (11,12), an inverter 26 (27,28), a second comparator 30 (32,34) are inserted into each channel, and the output of the control voltage source 35 is connected to the first in the comparators of all channels, each channel, the synchronizer input 7 (8.9) and the input of the driver 10, (11,12) of the reference voltage is connected to one of the three phases of the AC network, the output of the reference voltage generator is connected to the analog input of the multiplying DAC 23 (24,25) , the trigger input 13 (14,15) is connected to the synchronizer 7 output (8.9), and the direct and inverse outputs of the trigger 13 (14,15) - to the zero-body 16 (17,18), the output of which is connected to the reset input of the counter 20 (21,22), the output of the counter 20 (21,22) is connected to the digital input of the DAC 23 (24,25) whose output is connected to the second input of the first comparator 29 (30,31) and to the input of the inverter 26 (27,28) whose output is connected to the second input of the second comparator 32 (33,34). The output of each comparator 29-34 is connected to the first input of the corresponding element I 36-41, to the second inputs of which the direct and inverse outputs of the trigger 13 (14,15) are connected, respectively, and the outputs of the elements 36-41 are connected to the inputs of the formers 42-47 output pulses. The output voltage of the converter does not depend on the parameters of the input voltage. 1 il.

Description

the third channel0 A voltage driver 10 (11, 12), an inverter 26 (27, -, 28), a second comparator 30 (32.34) are entered into each channel, and the output of the source 35 of the control voltage is connected to the first inputs Comparators of all channels, in each channel the synchronizer input 7 (V, 9) and the input of the shaper 10 (11,12) of the reference voltage are connected to one of the three phases of the AC network, the output of the shaper of the reference voltage is connected to the analog input of the multiplying DAC 23 (24, 25), trigger input 13 (14, 15) is connected to the output of synchronizer 7 (8, 9), and direct and in the trigger outputs 13 (14, 15) to the null organ 16 (17-18),

the output of which is connected to the reset input of the counter 20 (21,22), the output of the counter 20 (21,22) is connected to the digital input of the DAC 23 (24, 25), the output of which is connected to the second input of the second comparator 32 (33, 34) "Output each comparator 29 - 34 is connected to the first input of the corresponding element I 36 - 41, to the second inputs of which the direct and inverse outputs of the trigger 13 (4, 15) are connected, respectively, and the outputs of the elements 36 - 41 are connected to the inputs of the output drivers 42-47 pulses "The output voltage of the converter does not depend on the input voltage parameters Yl of 1

The invention relates to electrical engineering and can be used in control systems of thyristor converters made according to a three-phase zero scheme, which are powered from low-power sources, tOe0 from sources with a large tolerance of variation in frequency and amplitude (10-15%).

The purpose of the invention is to improve the accuracy of the thyristor converter with changes in the parameters of the power supply voltage "

The drawing shows a block diagram of the device ;,

The device contains channels 1 - 3 according to the number of phases of the power supply network, to the input terminals 4-6 of which are connected the power supply phases0 Each channel 1 - 3 contains synchronizers 7 - 9 and drivers 10 - 12 of the reference voltage Counting, triggers 13 - 15 are connected to the inputs null-bodies 16–18 General for all channels generator 19 with phase-locked frequency iod-keys to the inputs of counters 20–22, the outputs of which are connected to the inputs of digital-to-analog converters (DAC 23–25, outputs connected to the inputs of the HE elements 26–28 and the first inputs of the first comparators 29 - 31, Pe stems second inputs of comparators 32 - 34 are connected to the output of the source 35 the control voltage ,, outputs of AND gates 36 - 41 are connected to the input of the-42 - 47 output pulses "

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The device works as follows.

The input of one of the channels 1 - 3 receives a sinusoidal alternating voltage after the step-down transformer of phase A. Synchronizer 7 and trigger 13 produce signals synchronous with positive and negative half-waves of the mains voltage, taken from the direct and inverse outputs of the trigger 13, respectively, of which zero The organ 16 generates pulses synchronous with the moments of the transition of the mains voltage through zero values. These pulses reset all the bits of the counter 20 into O. ca counter 20 enters the count mode and the multiplying DAC 23 supplied in double the number of code umenshayuschees 1 on arrival of each pulse from the generator 19 outputs a phase locked chastoty0 At the output DAC 23 is formed stepwise linearly decreasing voltage. The number of stages depends on the size of the counter 20 and the DAC 23 and is equal to

n 2N- 1,.

where N is the counter size

For example, when the counter size is N 10, the number of stages is equal to n 1023, the DAC forms an almost linear decreasing voltage0 Generator 19 with phase auto-tuning

frequency generates by comparing the signal from the inverse output of the counting trigger 15, arriving at the signal input of the generator 9, and the signal of the most significant bit of the counter 22, arriving at the comparator input of the generator 19, pulses with a frequency

f g (2fc) 2 where fc is the mains voltage frequency,

The reference voltage of the D / A converter 23 is a signal proportional to the amplitude of the mains voltage coming from the driver 10 of the reference voltage

The voltage from the output of the DAC 23

steps into the comparator 29 input and through the inverter 26 to the comparator 30 input. The LLATI 23 signals are compared by the comparators 29 and 30 with the control voltage, and at the time of their equality, the output signals of the comparators are generated using an AND 36 element at the positive value of the mains voltage from the signal of the comparator 29 is allocated a signal to the driver 42 output pulses

With the help of the element 37 at a negative value of the mains voltage, the signal coming to the shaper 43 of the output pulses

When the frequency of the power supply voltage changes, the frequency of the signal from the output of the generator 19 synchronously changes, the slope of the sawtooth voltage of the DAC 23 changes accordingly, which makes it possible to maintain the constant of the transfer ratio of the thyristor converter (TP) when the frequency of the power supply voltage changes.

When the amplitude of the supply voltage changes, the output signal amplitude of the driver 10 of the reference voltage and, accordingly, the steepness of the sawtooth voltage of the DAC 23, changes. This makes it possible to maintain the constant transfer coefficient of the power supply when the voltage amplitude changes, and also to eliminate the effect on the power supply. mains asymmetry. With a change in the amplitude of the supply voltage, a given current Tio is kept constant.

Similarly, the work of the other (2 and 3) channels takes place, taking into account the phase shift of the corresponding synchronization

0

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voltage of the reference voltage former can be configured as a peak detector,

The technical and economic effect consists in the absence of the need for adjustment during operation when changing the power source and changing the parameters of the power supply network to 10-15%. The accuracy of operation increases with changes in the frequency and amplitude of the power supply voltage j

Claims (1)

Invention Formula A device for controlling the thyristor converter, which contains in each channel a synchronizer, the input of which is intended to be connected to the mains supply, and the output connected to the input of the counting trigger with direct and inverse outputs, a zero-organ connected by the inputs with the direct and inverse outputs of the counting trigger trigger, and the output - with the reset input of the counter, multiplying the digital-analogue 1 converter, connected by digital inputs to the outputs of the counter, and the output - with the first input of the first comparator, the output of which is connected to the first input The first element And the second inputs of the first and second elements And are connected respectively to the direct and inverse outputs of the counting trigger, 5 and the outputs are connected to the inputs of the corresponding output pulse drivers, the outputs of which are intended to be connected to the control inputs of the thyristor converter common to all channels of the source the control voltage is connected to the second inputs of the first and second channel comparators, and the counting inputs of the channel counters are interconnected, characterized in that, in order to increase accuracy of operation with changes in power supply parameters, it is equipped with a generator common to all channels with a phase-locked loop and in each channel with an NOT element and a reference voltage driver, made in the form of an amplitude detector, and in each channel the first input of the second And element is connected to the output digital-to-analog converter through a series-connected element NOT and the second comparator, the second inputs of the first 0 five 71575280 -8 the second and second comparators are combined by the signal input connected to the inn, the driver of the reference by the full output of the counting trigger is connected to the input of the syncro-last channel, the comparator input terminal, and the output to the analog input; with the output of the higher bit of the count, the input of the digital-analogue transducer of the third channel, and the output from the bodies, common for all channels, the generation-counting inputs of the counters of all are ka-tor with phase-locked loop