SU1644336A1 - Forced switching device for thyristor converters - Google Patents

Abstract

The invention relates to power converter technology and can be used in a traction electric drive. The aim of the invention is to improve the energy performance and increase functional reliability. The device is intended for switching the thyristors of the converter 1 (for example, an inverter) and contains distribution thyristors 2 and 3, a power source 4 switching 11, 12,17 and 18 and the first charging TZ thyristors, separation 7 and 8 and the first charging 14 diodes switching LC circuits 19, 20 and 21, 22. Split 23 and second charge 24 thyristors, second charge 25 diode, bit 26 and 27 and return 28 - 31 diodes, as well as a switching three-pole transformer 32. The goal is achieved thanks to introduced resistors 5 and 6, separation diodes 14 and 25 and p thyristor 23 with an appropriate control algorithm implemented by the additionally introduced two-input logic element OR. 4 il. J

Description

The invention relates to converter technology and can be used in the forced switching nodes of autonomous voltage inverters of thyristor frequency converters of AC electric locomotives with asynchronous traction motors.

The aim of the invention is to improve the energy performance and increase functional reliability.

Figure 1 presents the scheme of the proposed device; figure 2 - diagrams of currents and. stress, explaining the principle of its action; FIG. 3 is a control pulse diagram; Fig. 4 is a functional diagram of the control signal generator.

The device (Fig. 1) contains a thyristor converter 1, anodic 2 and cathode 3 groups of distribution thyristors connected to the terminals of the converter 1, a power source 4 made in the form of a single-phase diode bridge and a filter capacitor connected by direct current leads to the terminals of resistors 5 and b, connected by other leads to the anodes and cathodes of the separation diodes 7 and 8, RCD circuits 9 and 10, connected in parallel to the switching thyristors 11 and 12, connected to the terminals of the separation diodes 7 and 8. the first pair of charge thyristor 13 and diode 14 connected to the outputs of the separation diodes 7 and 8 and to the common connection point of the thyristors

ON

fc

CO 00 O

11 and 12, RCD circuits 15 and 16, connected in parallel to the switching thyristors 17 and 18, connected to the terminals of the separation diodes 7 and 8, switching LC circuits 19, 20 and 21, 22, connected by the same terminals to the anode of the charging diode 14 and AC diagonal of a single phase bridge formed by switching thyristors 11, 12 and 17, 18 and other leads to separation thyristor 23, a second pair of charge thyristor 24 and diode 25 connected to the DC terminals of power source 4 and to conclusions of split thyristor 23, bottom diodes 26 and 27 connected to the outputs of switching thyristors, single-phase bridge of return diodes 28-31, connected by direct current leads to the outputs of switching thyristors 11, 12 and 17, 18, switching transformer 32, connected by conclusions of primary windings to anodes and cathodes of distribution thyristors 2 and 3, the terminals of the separation thyristor 23 and the discharge diodes 26 and 27, and the terminals of the secondary winding in the diagonal of the alternating current of the bridge of the return diodes 28 - 31, the control signal generation system 33 connected to the terminals of the thyristors 2, 3, 11 - 13, 17, 18, 28, 24.

The signal generation system 33 (FIG. 4) contains a frequency regulator 34, to the output of which a two-channel control pulse distributor 35 connected to each channel of drivers 36, connected to the output of which one-shot 37 and 38 are connected, drivers 39 and 40; connected by outputs to the thyristor control outputs, and inputs to the one-shot 37 and 38 outputs, a two-input logic element 41 coincidence (AND or OR) connected by its inputs in each control channel to the driver 36, the driver 42 pulses coupled to the output and to the output control unit forced commutation thyristors.

The device works as follows.

Let the capacitors 19 and 21 initially be charged and have a voltage sign on the to-1 interval (Fig. 2, without brackets) At the time ti to turn off the thyristors of the converter 1, the thyristors 11 and 23 are turned on by the control system 33, the switching capacitor 19 starts rebooting press along the contour: (+) 19, 20, 23, 2, 1, 11, (-) 19 to the lockable thyristor converter 1 to restore the valve properties through the anode group 2 of the distribution thyristors

The primary winding voltage of the switching transformer 32 is applied. After the thyristor of the converter 1 is locked, the capacitor 19 is recharged across the circuit. + 19,20,23,32,26, 11-19. With a time shift equal to 2/3 of the half-period of the natural frequency of the oscillating circuit, at the time point ta they turn on the thyristor 17 and the capacitor 21 of the second LC circuit begins to discharge along the (+) 21, 22, 32, 26, 17, (-) 21 circuit. At time t3, the recharging of the capacitor 19 ends, the first in order of recharging and the LC circuit to the opposite sign

voltage, while the voltage on the capacitor is lower than the original by

(1st lg / 2d),

0

five

0

five

0

five

0

where D is the quality factor of the oscillating circuit,

DCO source voltage at the switching capacitor at the time of switching

In the time interval t4-5, the capacitor 21 of the second in succession recharge of the LC circuit is recharged with a falling load current, as a result of which the voltage across it becomes higher than the initial voltage Uco. At time point te, the thyristor 13 is turned on, and the dose of the first in order recharge of the LC circuit is carried out along the (+) 4, 5, 13, 19,20,25, (-) 4 circuit. The charge is carried out in an oscillatory mode and the voltage on the capacitor 19 becomes higher than the voltage of the source 4 of the power supply. The difference of these voltages applied to the thyristor 13 and diode 25 ensures reliable restoration of the valve properties, and the charge thyristor 13 is turned off along the circuit ( -I) 19, 13, 5, 4, 25, 20, (-) 19.

In this case, the excess energy of the switching capacitor 19 along the reverse diode circuit 9, the separation diode 7 and the resistor 5 is output to the circuit of the power source 4. The current, due to the resistor 5, decreases aperiodically and the voltage on the capacitor 19 is limited at the voltage level of the power source 4.

At time ts, the thyristors of the cathode group of the converter 1 are switched. In this case, one of the distribution thyristors of the cathode group 3 switches on the switching thyristor 18, separator thyristor 23, as a result of which the capacitor 21 is recharged along the circuit: (4) 21. 18, 1.3 , 23, 22. (-) 21. The voltage of the primary winding of the switching transformer 32 is applied through

distribution thyristors to switchable thyristors of the converter 1. After locking the thyristor of converter 1, the capacitor 21 continues to recharge on the circuit: (+) 21, 18, 27, 32, 23, 22, (-) 21. At time tg turn on the thyristor 12 first LC circuits and capacitor 19 are recharged around the circuit: (+) 19, 21, 27, 32, 20, (-) 19.

At time ti3, the charge of the first in turn-on order of the LC circuit 21 and 22 is performed. To do this, charge thyristor is turned on, and the charge of the capacitor in the oscillating mode is carried out along the circuit: (+) 4, 24, 22, 21, 14 , 6, (-) 4. The surplus energy of the switching capacitor 21 along the (+) 21, 22, 24, 4, 6, 8, 16, (-) 21 circuit is output to the capacitor of the power supply 4 according to an aperiodic law. The voltage difference between the capacitors 21 and 4 is applied to the thyristor / 24 charge diode and the diode 14, ensuring reliable restoration of valve properties, and the thyristor 24 is locked.

Further, the electromagnetic processes are repeated similarly.

In idle mode, the device operation algorithm remains unchanged, as a result of which capacitors 19 and 21 switching LC circuits are charged through one commutation.

The control signal generation system 33 of the forced switching device (FIG. 4) consists of a frequency controller 34 and a pulse distributor 35 made in the form of two control channels on the logic elements.

The control signal generating system 33 according to the control diagram (Fig. 3) operates as follows. Frequency Uf is applied to the input of frequency adjuster 34 (set by output frequency, Figures 1 and 3). From the output 34, for each phase of converter 1, two signals are generated (for example, + UAi - UA). According to the control pulse diagram (Fig. 3), on the falling edge of these signals, the driver 36 generates pulses in each control channel to the control terminals of the thyristors 11 and 18 and to the inputs of one-shot 37 and 38. The latter form pulses equal in duration to time intervals ti -12 and ti-te, respectively, on the back edges of which amplifiers-formers 39 to 41 form control pulses arriving in each channel at the control outputs and thyristors 13,17 and 23 in the first channel and the control terminals of the thyristors 12, 23 and 24 in the second control channel.

Introducing two resistors and connecting them to the power supply buses and to

the outputs of the separation diodes allows the output of the excess switching energy through the circuit of the reverse diodes according to aperiodic law, as a result

the voltage across the capacitors is limited at the voltage level of the power source.

In addition, the specified connection of resistors in series with the charging

thyristors and diodes make it possible to charge the capacitors of the LC circuits in an oscillatory mode and to ensure reliable restoration of the valve properties of thyristor charges to the end of the switching process.

Claims (1)

Invention Formula A thyristor forced switching device for a converter containing two pairs of consistently connected switching thyristors connected by common connection points of the corresponding terminals to the corresponding terminals of counter-connected switching diodes, RCD circuits connected in parallel to the switching thyristors, and discharge and return diodes connected by their respective terminals to common points of connection of the anodes and cathodes of commuting thyristors, the first and second commuting LC circuits, The first and second charging thyristors connected by the first leads to the corresponding junction points of the sequentially connected switching thyristors, cathodes connected to the first lead of the first and second leads of the second LC circuit, respectively, and anodes connected to the separation diode cathode and to the positive power supply bus , made in the form of a valve bridge with a filter capacitor, switching transformer with two primary and one secondary windings, connected by primary leads to the corresponding conclusions of the commutating LC circuits and discharge diodes, and the secondary leads to the diagonal of the alternating current of the single-phase bridge of the return diodes, the anode and cathode groups of the distribution thyristors connected by the corresponding leads to the outputs of the thyristor converter and the corresponding conclusions of the primary windings of the switching transformer, as well as the control unit, which includes the pulse shapers of the control of the switching, distribution and charging thyristors, characterized by By the fact that, in order to improve energy performance and increase functional reliability, two resistors were added to it, connected to power supply buses and dividing diode terminals, the first and second charging diodes, and anodes connected to the first terminal of the SECOND and second terminal respectively. the first commuting LC circuits, and the cathodes to the anode of the separation diode and the negative bus of the power source, the separation thyristor, the anode and the cathode a house connected to the second terminals of the first and second commuting LC circuits, as well as a two-input logic element OR, with its inputs connected to the outputs of those pulse shapers that are connected to the control inputs of the switching thyristors of the first of the restarted LC circuits, and the output through the input of the amplifier-shaper connected to the control input of the separation thyristor. № # Im No S 19 th to B $ -yy yy kjjft, “2,3,11-13, L-18,23-24 FIG A