SU516170A1 - Device to control the thyristor converter - Google Patents

Description

one

The invention relates to a transformer 1.; B technology and is intended to control a thyristor converter, consisting of two inverters and a reversible bridge, with the aim of obtaining an output voltage of an adjustable low frequency.

Control devices of a thyristor converter of this type are known, comprising a reference frequency generator, a reference frequency generator, pulse amplifiers, frequency dividers, decoders.

The disadvantages of the known devices are the unsatisfactory adjustment characteristics and the instability of the output frequency, due to the fact that the output frequency is the Kait difference in the reference and reference frequency.

To improve the stability of the output frequency while maintaining a wide control range in the proposed device, the zero output of the reference frequency generator is connected to the input of the first frequency divider and through the differentiating chain to the input of the OR cell, the output of the reference frequency generator and the single output of the reference frequency generator , the output of which is connected to the second input of the “OR. The output of the cell "OR connected to the input of the second frequency divider, and the outputs

frequency dividers are connected to the inputs of the corresponding pulse formers.

FIG. 1 is a block diagram of a converter and a control device; in fig. 2 shows the voltage diagrams at the input and output of the reversing bridge; in fig. 3 is a schematic diagram of the control device; in fig. 4 - time diagrams of operation of individual units of the control unit.

The block diagram (Fig. 1) contains a reference frequency generator 1, a reference frequency generator 2, a pulse adder 3, pulse shapers 4, 5, inverters 6, 7, and a reversing bridge 8.

Claims (1)

The reference frequency generator controls the first inverter 6 through the imager 4 and drives the master frequency generator to the input of the pulse array 3, the second input of which receives pulses from the output of the reference frequency generator. The total frequency pulses through the driver and impulses 5 control the second inverter 7. As a result, when adjusting the frequency of the generator 2, for example, in the region of low frequencies, the total frequency will differ slightly from the frequency of the generator 1 operating at a high carrier frequency. Due to this, Bozmol appears: the smoothness of the regulation of infra-low frequencies. In addition, the stability of the output oscillations is determined only by the stability of the generator 2, since the instabilities of the generator 1 are mutually compensated when the output voltages of the two inverters 6 and 7 are added together. After rectifying the total voltage (Fig. 2, a) with a reversible thyristor bridge 8, the output form the voltage of the converter is as shown in fig. 2, b. The schematic diagram of the proposed device includes a reference frequency generator 9, a master frequency generator 10, a synchronization block I, a trigger 12. A synchronization block consists of a trigger 13, a matching circuit 14, a trigger 15, and differentiating values 16. The circuit also contains a cell OR 17, dividers 18 and 19 frequencies on the trigger 20, the pulse shapers 21 and 22. The device operates as follows. The pulses 23 of the reference frequency generator (Fig. 4) are fed to the input of the trigger 12, which at its two outputs produces pulses 24, 25 shifted relative to each other by a time equal to the period of the input frequency. The pulses 26 of the master frequency generator, arriving at the input of the trigger 13, settle its IB single 1 state, in which the resolving potential comes from its output to the input of the coincidence circuit 14. As a result, pulses from a single output of trigger 12 pass through circuit 14 to the counting input of trigger 15. The first impulse, passed to the input of trigger 15, transfers it to the “O” state, while at its output a negative voltage drop occurs, which does not change trigger state 15. The second pulse, entering the trigger input 15, translates it into the state "1, forms a positive voltage drop at its output, which, passing through the differentiating slot 16 to the trigger input 13, returns it to its original state" Oh, thereby closing the circuit 14 coinciding and stopping the arrival of pulses at the trigger input 15. As a result, for each pulse of the input frequency, the synchronization unit produces a gate at the trigger 15 output, the fronts of which coincide with the fronts of the reference frequency coming from the single output of the third trigger 12. Through the differentiating circuit 16 arrive at the input of the cell "OR 17, to the second input. Which, through the differentiating circuit 16, impulses come from the zero output of the trigger 12. Thus, the scheme" OR 17 sums up two pulse followers spine 27, the fronts of which are synchronized reference pulses "spaced frequencies and hence never sovnadayut time. This total pulse sequence is not suitable for controlling the inverter thyristors due to the "uniformity of the pulse following period. However, by dividing the indicated sequence of trigger 20 of the frequency divider 19 (see 28-32), the non-uniformity of adjacent periods decreases and, with a division factor of 27-210, becomes negligible. The frequency divider 18 reduces the ratio of the input and output frequencies. In this case, the possibility of smooth control in the region of infra-low frequencies by the generator 10 of the driving frequencies, operating in the region of medium frequencies, appears. FIG. 4, positions 32 and 33 denote the pulses of single outputs of the triggers 20 of the frequency dividers 18 and 19, positions 34, 35 the output pulses of the former 21, and positions 36, 37 the output pulses of the former 24. Thus, on the formers 21 and 22 pulses are formed by two sequences of pulses (with one adjustable), which allow to obtain a frequency-controlled sinusoidal voltage in the range of low and infra-low frequencies. Claims An apparatus for controlling a two-inverter thyristor converter with an output reversible rectifier comprising a reference frequency generator, a master frequency generator, a synchronization unit, an OR cell, a frequency splitter and pulse drivers, characterized in that, in order to increase the output frequency stability while maintaining a wide control range, the zero output of the reference frequency generator is connected to the input of the first frequency divider and through a differentiating chain to the input of the cell "OR, The output of the master frequency generator and a single output of the reference frequency generator are connected to the corresponding inputs of the synchronization unit, the output of which is connected to the second input of the cell “OR, the output of the cell” OR is connected to the input of the second divider, frequency. The outputs of the frequency dividers are connected to the inputs of the corresponding pulse shapers.