SU1325640A1 - Alternating voltage-to-direct voltage converter - Google Patents

Abstract

The invention relates to converter technology, in particular to valve converters with advanced switching. The purpose of the invention is to increase reliability, improve mass and energy performance. The effect of the transducer is achieved with the exception of an equalizing reactor when parallel operation of two bridge rectifiers on diodes 8-19. In this case, a four-rod transformer I with auxiliary transformers is used (L S Fi.

Description

132

with hanks 20-26 and low-power innertor with control system. Transformer 1, in addition to the basic function, also functions as an equalizing, switching and current-limiting reactors. The presence of a low-power triple-frequency inverter allows you to remove the peak voltage at idle. As the load increases, ph1 changes.

The invention relates to converter technology, in particular to valve converters with advanced switching.

The purpose of the invention is to increase reliability, improve weight, size and energy performance.

Figures 1 and 2 are schematic diagrams of the device; FIG. 3 shows graphs for the operation of the device.

A two-stroke six-phase converter (Fig. 2) contains a four-core converter transformer 1 with network windings 2-4, valve windings 5-7 connected between the output and AC current of three-phase valve bridges assembled on valves 8-19, two pairs of auxiliary windings 20-25 on the main cores of the magnetic circuit and auxiliary winding 26 on the fourth core of the magnetic circuit. The cathodes of the valves 8-10, 14-16 are combined into a common point and form a positive output terminal 27, which is connected via a separating diode 28 to the first input terminal 29 of the inverter 30 (figure 2). The negative output terminal 31 is formed by the anodes of the valves 11-13, 17-19. Inverter 30 has a second input output 32, and primary output winding 35 of output transformer 36 is connected to its output voltages 33 and 34. Three secondary windings 37-39 of output transformer 36 are connected through three pairs of parallel-connected thyristors 40-45 each separately to the first auxiliary windings 23-25 conversion transformer 1, and four 640

for the triple frequency voltage supplied to the auxiliary windings 23-25 through the voltage inverter and thereby creates a leading switching current of the valves, which allows to regulate the reaction power consumed by the converter without the use of commuter capacitors. 3 il.

This winding 46 of the output transformer 36 is connected through the fourth pair of parallel-connected thyristors 47 and 48 to the second auxiliary windings 20-22 of the converter transformer 1, which are connected to an open triangle. The converter also contains a three-phase current sensor 49, the first 50 and second 51 input terminals of the control system, to which the auxiliary winding 26 of the fourth rod and the three-phase current sensor 49 are connected. The control system is based on

a triple frequency sensor 52, two single-oscillators 53 and 54, a control unit 55, a decoder 56, a thyristor control unit 57, and three pulse shapers 58-60.

The three-phase current sensor 49 is terminated on the basis of three current transformers 61-63, the primary windings of each of which are busbars of valve windings 5-7 of the diode bridge

64, to the AC input of which the secondary windings are connected - 61-63 current transformers, and a potentiometer 65, the slider of which is the output terminal of current sensor 49.

Inverter 30 is made on fully controlled 66-69 valves with a reverse current diode bridge and contains an input filter, represented by a capacitor 70, and an output filter consisting of a series oscillating circuit, including a choke 71 and a capacitor 72, and a parallel oscillating circuit, including choke 7.3 and capacitor 74 tuned to triple line frequency.

The triple frequency sensor 52 contains a compact 75, connected by an input to the first input terminal 50 of the control system, front formers 76 and 77 front edges connected by inputs to the comparator output. 75, trigger 78 and circuit OR 79.

Control block 55 comprises a second comparator 80 connected by an input to a second input terminal 51 of the control system, a second trigger 81, and a logic inverter 82.

The decoder 56 is assembled on the schemes And 83-88, the second and third schemes OR 89-90 and the third trigger 91.

The thyristor control unit 57 is made on the basis of three AND 92-94 circuits of a six-bit shift recorder 95, a logical inverter 96.

As pulse formers 58-60, the most suitable are formers with a high-frequency generator, in which the duration of the output pulses correspond to the duration of the input signals.

The device works as follows.

During normal operation of a two-stroke six-phase converter, two three-phase bridge rectifiers assembled on gates 8-13 and 14-19 enter into parallel operation. In parallel operation of bridges, a rectified voltage is established, the magnitude of which is the average between the instantaneous values of the phase voltages alternately of counter-parallel operating valve windings 5-7. The difference of the instantaneous values of the phase voltages of counter-parallel operating phases is triangular and a triple frequency with respect to the frequency of the mains supply with an amplitude equal to half the amplitude of the phase voltage of the valve winding.

To equalize the instantaneous values of the load currents smaller than 40 to the auxiliary windings 20-22 connected in an open triangle, a triple frequency voltage is applied (FIG. 3) through counter-connected thyristors 47 and 48 45 of the winding 46 of the output transformer of the inverter 30. Under the action of this, the triple frequency current flows through the auxiliary windings 20-22 from the main rods, which creates

 phase voltages of counter-parallel-50 flows of zero sequence in

Transformer 1 with a four-rod magnet-conductor was used in operation of valve coils in the converter. Under the action of the triple frequency voltage generated by the converter, a triple frequency equalizing current flows through the valve windings of parallel operating phases, which creates unidirectional core rods. These flows are also closed along the magnetic conductor of the fourth rod, with the result that the current of the auxiliary windings 20-22 is low. 55 Thus, the alignment of instantaneous values of voltages in parallel to the operating phases can be accomplished by passing a triple frequency magnetizing current

currents in the main terminals of the transformer. For streams of zero sequence, a transducer in the converter has a path along the magnetic conductor of the fourth rod in an unsaturated state. Due to this, there is a high zero sequence resistance in the equalization circuit.

TI X,

commensurate with resistance

magnetizing transformer.

which sufficiently limits the equalizing current of the converter. Surge current

does not exceed 1-2% of the amplitude of the rated current of the valve winding with the cross section of the fourth rod 30-40% of the cross section of the main rods.

Thus, to implement the parallel operation of two three-phase bridges with the duration of the valves 120 without taking into account the angle of switching, there is no need to use bulky two-phase equalizing

reactors. At the converter load current, called critical 1 and equal to 1-2% of the nominal rectified current, at which three-phase bridges start parallel operation, the rectified voltage curve Vj and the phase voltage curve Ufj have corresponding forms (Fig. ). From the zero-sequence flows, a triple frequency voltage Uj is applied to the auxiliary winding 26 of the fourth rod, which is the signal for the triple frequency sensor 32.

When the load currents are smaller, the auxiliary windings 20-22, connected in an open triangle, are supplied with a triple frequency voltage (FIG. 3) through the oppositely connected thyristors 47 and 48 of the winding 46 of the output transformer of the inverter 30. Under the action of this voltage auxiliary windings 20-22 with the main rods triple frequency current flows, which creates

streams of zero sequence in

main rods x. These flows are also closed along the magnetic conductor of the fourth rod, with the result that the current of the auxiliary windings 20-22 is low. 55 Thus, the alignment of instantaneous values of voltages of parallel operating phases can be accomplished by passing a triple frequency magnetizing current

windings 20-22 main core1. Auxiliary windings 23-25 of the main rods can also create advanced switching of valve leyg currents.

When the load currents are large, T-, thyristors A7 and 48 are closed and alternately parallel-parallel thyristors 40-45 turn on and the auxiliary windings 23-25 of the converter transformer are applied by the sinusoidal voltages Uj, - Uj (fig.3l, m, n) triple frequencies, which are transformed to the winding valve {) 1e 5-7. In this case, the leading edge of the shape of the phase voltage curve Uj, and. , 11 of the valve windings 5-7 varies (Fig. 3f, dotted line). In this case, the equality of the instantaneous values of the voltage of the valve windings connected to the valves terminating the work and entering into operation occurs earlier than with natural switching on, i.e. unlocking of the valves entering the work takes place ahead of the time of their natural unlocking at a certain angle N (FIG, ZF). With a further increase in the load current, the phase of the triple frequency voltage at the output of the inverter 30 gradually changes to a certain limit through the system, which automatically leads to an increase in the advance angle of, At the same time, the load current is controlled by the sensor 49 current. The output from the current sensor output is proportional to the load current on the control system.

The sensor 52 triple frequency connected to the auxiliary winding 26 of the fourth rod. The voltage on the auxiliary winding 26 is shown in FIG. 3A. The comparator 75 forms at the output a bipolar voltage with reversals from one polarity to another at the time of the voltage transition on the auxiliary winding 26 through zero. The front 76 and rear 77 front drivers, connected to the output of the comparator 75, control trigger 78, the forward and inverse outputs of which form monopolar rectangular pulses synchronized with a triple frequency of the auxiliary winding 26. Outgoing circuit OR 79 a pulse train is formed with cha; toto 6f5 where f is the frequency of the industrial network. The signals at the outputs of the comparator 75, the direct output of tripler 78 and the OR circuit 79 are shown respectively in Fig. 3b. in, city

The comparator 80 of the control unit 55 monitors, on the screens of the current sensor and the reference voltage 49, the moments of the transition of the output current of the converter through the value Ijc.

At current values greater than 1, under the influence of a comparator, a single signal is formed at the direct output of flip-flop 81, and at currents less. ha its reverse output.

A single vibrator 53 serves as a delay line and produces a pulse duration of 2/3 of the 6f frequency period. The output signal of a single vibrator is shown in FIG. Second

A single-vibration 54 produces a pulse duration for gating the operation of block 56, and they can also be used as auxiliary pulses for

controls fully manageable

the inverter valves 30. The signal at the output of the one-shot 54 is shown in FIG.

Consider the mode of the system

Inverter control at converter output currents greater than 1. At the direct output of the second flip-flop 81 of the control unit 55 there is a single signal which, as

the permissive signal is fed to the second inputs of the first 83 and seventh 92 schemes I. At the same time, the output signal of the first one-shot 53 is fed to the inputs of the third 85 and fourth 86 schemes

And, to which the output signals of the first trigger 78 also arrive. Accordingly, on the inverse outputs of the second 89 and third 90 OR schemes, signals are generated (Lig.Zh and s). The Sigal at the direct output of the trigger 91 is shown in FIG. The output signals of the trigger 91 through the driver of the 58 pulses, performing the role of amplifying galvanically isolating

cascades, are fed alternately to the inputs of the fully controlled valves 66, 69 and 67, 68, which are located in the opposite arms of the post inverter.

The rectangular voltage generated by the fully controlled valves of the inverter 30 is converted into sinusoidal voltage by means of the elements of the output filter and fed to the output terminals 33 and 34 of the inverter. The curve of the output voltage of the inverter 30 (Fig. 3k) shows that the output signal of the inverter 30 is shifted relative to the triple frequency signal of the auxiliary winding 26 for the duration of the pulse generated by the single vibrator 53.

The cut-off diode 28 eliminates the re-ig 36 of the inverter 30 (fig.Zu), which the pumping of energy between the input filter is phased with the voltage of the triple inverter 30 and the load of the converter. Subsequently, from the secondary windings 37-39 of the output transformer 36, the output voltage of the inverter is redistributed between the first auxiliary windings 23-25 of the converter transformer from 15 to 15

pulse generators 60 and then the inputs of the fourth pair of thyristors 47 and 48. As a result, the output auxiliary voltage of the secondary winding 46 of the output transformer is applied to the second auxiliary windings 20-22 of the converter transformer 1, including into the open triangle

frequencies.

Claims (1)

Invention Formula AC to DC converter containing three- by the power of three pairs counter-parallel a phase four-core transformer transformer, the windings of which are switched on thyristors 40-45 (fig.3l, 2p roy are located on the rods by a magnet, n). The necessary order is followed by a wire, while the network windings — no pulses on thyristors 40–45 — are connected into a star, each of the four is processed with the help of a block 57 control rods equipped with auxiliary laziness thyristors. In the current mode of the converter, the large-25 windings of the main rods of the IOJKP circuit included the output signals of the circuit And 83, successively in the open triangle, the output nickname, three-phase current sensor, the signal of the one-vibrator 53 (FIG. 10), Based on three single-phase inverting logic inverter current transformers, the primary windings 30 of each of which are busbars of winding windings, and the secondary windings are connected in a star and through a three-phase diode bridge with ground 96 are fed to the input of the six-bit shift register 95. The signals at the outputs of the first, second and sixth cells are shown in fig.Zo, p, p. At the outputs of the pulse shapers 59, the order of the pulses at the inputs of the thyristors is indicated. one When the converter currents are less than Ij, the And 83 and 92 circuits are closed from the direct output of the second flip-flop 81. The control pulses from the thyristors 40-45 inputs are removed. Here, under the influence of the comparator 80, the signal passes through the logical inverter 82 and is formed on the inverse of you. during the trigger 81, which opens the circuits of And 84, 93 and 94. Since the pulse duration of the second one-shot 54 is insignificant, the signal of the third trigger almost coincides in phase with the voltage of the initial triple frequency (Fig. 3a). The output signals of the OR circuits 89 and 90 are shown in Fig. 3c, t. The output voltage of the secondary winding 46 of the output transformer 36 of the inverter 30 is shown in Fig. Lo. In addition, the voltage from the direct and inverse outputs of the third trigger 91 through the circuits And 93 and 94 comes 35 45 cathode group connected to a potentiometer, the slider of which is the output terminal of the current sensor connected to the first input terminal of the inverter control system, the second output connected to the auxiliary . ,, the supportive winding of the fourth rod - 40 " n, the free output of which is grounded, an inverter made in a bridge circuit on fully controlled vents with a reverse current diode bridge and connected direct current leads through an input filter and a separating diode to the output leads, and alternating current leads to an output filter. Moreover, the inverter control system is made on the basis of a triple frequency sensor, a single vibrator, a control unit, a decoder and the first pulse generator, and the triple frequency sensor contains a first comparator connected by an input to the first input branch of the control system, front and rear edge drivers connected by inputs to the output comparator, trigger55 pulse generators 60 and then the inputs of the fourth pair of thyristors 47 and 48. As a result, the output auxiliary voltage of the secondary winding 46 of the output transformer is applied to the second auxiliary windings 20-22 of the converter transformer 1, including into the open triangle 36 invert sphazirova frequencies. 36 of inverter 30 (FIG. 13), which is phased with a triple voltage. Invention Formula AC to DC converter containing three- five five cathode group connected to a potentiometer, the slider of which is the output terminal of the current sensor connected to the first input terminal of the inverter control system, the second output connected to the auxiliary ,, the supportive winding of the fourth rod- 0 „ n, the free output of which is grounded, an inverter made in a bridge circuit on fully controlled vents with a reverse current diode bridge and connected direct current leads through an input filter and a separating diode to the output leads, and alternating current leads to an output filter. Moreover, the inverter control system is made on the basis of a triple frequency sensor, a single vibrator, a control unit, a decoder and the first pulse generator, and the triple frequency sensor contains a first comparator connected by an input to the first input branch of the control system, front and rear edge drivers connected by inputs to the output comparator, trigger5 The rep and OR circuit, connected by inputs to the outputs of the front and rear edges, the control unit contains a second comparator connected by the input to the first input terminal of the control system, the second trigger, whose S input is directly, and the R input through the logic inverter is connected to the output of the second comparator, the decoder contains six two-input circuits And, the first input of the first circuit And connected to the output of the one-shot, the second inputs of the first and second circuits And connected respectively to the direct and inverse outputs of the second three The first, third, and fifth, and fourth and sixth, And first connected inputs are connected to the direct and inverse outputs of the first trigger, respectively; the second inputs of the third and fourth And connectors, and the fifth and sixth And outputs are connected to the first and second outputs, respectively. the second AND, second and third two-input circuits OR, the second is connected by inputs to the outputs of the third and fifth schemes AND, a third is connected by inputs to the outputs of the fourth and sixth And, the third trigger connected by inputs to outputs respectively The third and third OR circuits, and the third trigger outputs through the first pulse shaper are connected to the inputs of fully controlled inverter valves, characterized in that, in order to increase reliability, improve mass and energy indicators, two three-phase valve bridges are added, the output transformer of the inverter, four pairs of parallel-connected thyristors, a second one-shot, a thyristor control unit, second and third pulse shapers, with the main transducer rods The transformer is supplied with additional auxiliary windings, each with one valve winding system, which is connected between the input With dimeric current of three-phase VCR bridges, with these same-named conclusions of the constant three-phase current of the 1st valve bridges interconnected and form the first and second output terminals of the converter, the additional winding of the output transformer of the inverter is connected to the output filter of the inverter. auxiliary windings of the main transducer rods. the formatter is connected, each through three pairs of parallel-connected thyristors, respectively, to the three secondary windings of the output transformer of the fourth inverter; the secondary winding of the output transformer of the inverter is connected through the fourth pair of parallel-connected thyristors to the main auxiliary windings of the main rods of the converter transformer connected to the open a triangle, the first input of the second circuit AND the inverter control unit is connected via the second one vibrator to the output of the OR circuit of the triple frequency sensor; the thyristor control unit contains the seventh AND circuit, which is connected to the first input through the second logical inverter to the output of the first And circuit the output of the second trigger, a six-cell scaling circuit, connected to the output of the seventh circuit And, and six outputs of the counting circuit through the second pulse shaper are connected to the inputs of, respectively, three pairs of anti-parallel connected thyristors, the eighth and ninth And circuits, which are connected to the direct inverse output of the third trigger, respectively, by the first inputs. the second inputs are connected to the inverse output of the second flip-flop, and their outputs through the third pulse shaper are connected to the inputs of the fourth pair of counter-parallel-connected flip-flops, . ..z :. Ut  90 Ug, a. d. 3. -T -;. /,., 1. 9d Editor M. Blanan Compiled by E. Melnikova Tehred L, Serdyukov Proofreader L. Patay Order 3122/53 Circulation 659 Subscription VNIKLI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d, 4/5 Manufacturing and printing company, Uzhgorod, st. Project, 4