SU955502A1 - Device for controlling m-phase gate converter - Google Patents

Description

The invention relates to electrical engineering, in particular to devices. for controlling network-driven inverters, direct frequency converters operating from autonomous sources of energy with deep changes in frequency and amplitude, and the supply voltage.

A device for controlling a valve converter, operating according to a vertical principle with a sawtooth reference voltage, contains reference voltage generators synchronized with the supply voltage, reference devices, distributors, output amplifiers. This device allows to ensure reliable operation of the converter in transient conditions, the functioning of the converter in intermittent current mode, to a reactive load with a variable power factor, since the duration of the trigger pulses corresponds to the duration of positive anode voltage applied to the power thyristors and in dynamic modes 1.

However, it does not ensure the efficiency of the valve converter with deep changes in the frequency of the supply voltage.

The closest in technical essence to the present invention is a device for controlling a t-phase valve converter, containing an output amplifier, a synchronizer connected to the mains, each of the outputs which is connected to one of the m sawtooth voltage generators and to the inputs

15 frequency to voltage converter, the output of which is connected to other combined inputs of the saw-tooth voltage generators, the output of each of which is connected

20 to the input of each of the m comparators, the other inputs of which are combined and connected to the control signal source, and the outputs of the comparators are connected to the inputs of the t-phase distributor. This device, through the use of a frequency-to-voltage converter, ensures the operability of a deep-frequency frequency converter converter.

30 supply voltage Sz. The drawback of the device is that when it is used, the process of locking the thyristor begins immediately after the removal of the control pulse. In this case, an excess charge is accumulated in the control base of the thyristor, for which it takes some time to dissolve, which increases the time that the thyristors are locked and can cause an inverter operating in the inverter mode. The purpose of the invention is to increase the reliability of the device. The goal is achieved by the fact that the device for controlling the t-phase valve converter is equipped with a divider, an adder, m additional EI comparators, and m AND elements, with additional comparators connected to the output of the corresponding sawtooth generators, And elements included between the distributor and the output amplifier, divider. connected between the frequency converter in the voltage and one input of the adder, the other input of which is connected to the source of the control signal, and the output is connected to the common input of additional comparators, the output of each of which is connected to the input of each of the elements of the leading phase. FIG. 1 is a schematic of a device for controlling a t-phase valve converter; in fig. 2 - timing charts of the device. The device for controlling the .t-phase valve converter (ig. 1) contains a t-phase synchronizer 1 connected to the mains. Each of the m outputs of the synchronizer 1 is connected to the inputs of the frequency converter 2 to voltage and to each of the m generators FOR, 3 V ... 3m of the sawtooth voltage, the output of each of which is connected to the input of each of the m Comparators 4A, 4V. 4t. and each of the additional. comparators 5A, 5V ... 5t. The other inputs of the control comparators are combined and connected to the source 6 of the control signal and the output of the adder 7. Between the output of the PI5 generator and the other input of the summator of the matrix 7, a divider 8 is turned on, and the output of the adder is connected to the combined inputs of the comparators. The outputs of the control comparators are connected to the m inputs of the distributor 9, X1 each of the m outputs of which are connected to each of the m elements AND Yua, 10V ... Yut, the outputs of which are connected to the inputs of the output amplifier 11. The output of each of the additional comparators is connected to the input of each of the elements 10 advanced azy- (5V to the JuD; 5t-1 to Yu; 5t to the YuA) The device works as follows. At the outputs of synchronizer 1, signals are formed (plot 12, 13, 14, Fig. 2), corresponding to the zero crossings of the corresponding supply voltage. At the output of the frequency converter 2 into a voltage, a voltage is formed (graph 15, fig. 2) proportional to the frequency of the supply network -K.f, pf -, V I; where K, - transfer coefficient; f is the voltage frequency of the power supply with & .. At the output of the generators .3 of the sawtooth voltage (GPN), voltages are formed synchronized with the supply network and represented in phas A and B on graph 16, 17 (Fig. 2), The law of variation of the linear part of these stresses is described by the expression (2) .. i where RC is the constant time of the FPG; 1 - the current value of the angle (rad.); Llg, (-K fj (in accordance with (1). If the instantaneous values of the output voltage of the generator 3 sawtooth voltage and the output voltage of the source 6 of the control signal (Uijnp; graph 16, 17, Fig. 2), comparators 4 switch (plot 18, 19, fig. 2). The switching front of the comparators 4 corresponds to the thyristors control angle of the gate converter, the value of which can be determined from (2) as., RcaTiUynp "or by time" follows from (3), ot control does not depend on f. Signals are generated at the output of the distributor 9 (plot 20, 21, .- 2), the front of which corresponds to the angle of control of the corresponding phase, and the cutoff corresponds to the angle of control of the subsequent phase (correspond to the conduction intervals of the thyristors of the valve converter). At the output of divider 8, a signal is generated

where K is the transfer coefficient

tel 8.

A voltage is formed on the output of the adder 7 (plot 17, fig. 2)

K

: b)

Uj Uynp K „

Additional comparators 5 are switched at time points (plot 22, fig. 2), determined by the ratio obtained by converting (5) and (6) t

i ()

h

f

The outputs of the logic elements And 10 form signals (graph 23, 24, Fig. 2), the duration of which is less than the conduction interval of the thyristors of the converter converter by the amount S, which can be determined in accordance with (4) and 7)

Iv)

RC

(eight)

li

Solution (8) is the expression

RC

s

(9)

As follows from (8), the value does not depend on Uynp; fi and at constant values of RC and Kj is a constant value.

The pulses, finally formed in duration (graph 23,. 24, Fig. 2), go to the output amplifier 11 and further to the control transitions of the thyristors of the valve converter.

In order to improve the thyristor lock-up mode of the converter converter, the value of S is selected for the particular type of output amplifier of the trigger pulses and the type of thyristors used, based on the dissipation condition during the 8-charge overload time in the control base of the thyristor. At the same time, the power of the VOLT is provided.

the characteristics of the thyristors for the entire time the positive anode voltage is applied and optimal conditions are created for locking the thyristor starting from the end of interval 8 (for BKJHO, the next thyristor). The independence of the value of o from the current values of f and Uijnp allows us to maintain optimal conditions for locking thyristors in the process of changing the frequency of the supply voltage and adjusting the angle of control.

Claims (2)

Apparatus of the Invention A device for controlling a T-phase valve converter, 5 containing an output amplifier, a synchronizer, each of the m outputs of which is connected to one of the m sawtooth voltage generators and to the converter frequency inputs to a voltage, the output of which is connected to the other combined inputs of the saw voltage generator, the output of each of which is connected to the input of each of the m control comparators , the other inputs of which are combined and connected, with,. the source of the control signal, and the outputs of the comparators are connected to the inputs of the PT-phase distributor, characterized in that, in order to increase reliability, it is equipped with a divider, an adder, m additional comparators and m elements, and additional comparators are connected to 5 outputs of the corresponding sawtooth generators, the elements And are connected between the distributor and the output amplifier, the divider is connected between the converter 0 frequency in the voltage and one input of the adder, the other in which is connected to the source of the control signal, and the output is connected to the common input of additional comparators, 5 the output of each of which is connected to the input of each of the elements And the advanced phase. Sources of information taken into account in the examination 0 1. Swiss patent 493158, cl. H 02 R 13/16, 1970. 2. USSR author's certificate 611284, cl. H 02 R 13/16, 1975. 7l f r r f FFF-FFF FT fc pUt pfctgjJuLAj FIG. I n i