SU1636956A1 - Variable-ratio constant-voltage transformer - Google Patents

Description

one

(21) 4313064/07; 4331499/07

(22) 10/05/87

(46) 03/23/91. Bgol. № 11

(71) Ural branch of the All-Union Scientific Research Institute of Railway Transport

(72) L. G. Koshcheev

(53) 621.314.57 (088.8)

(56) Bedford. B., Hoft R. Theory of autonomous inverters. -: M .: Energie, 1969.

USSR Author's Certificate No. 474084, cl. H 02 M 3/315, 1975.

(54) CONSTANT POWER CONVERTER CONSTANT WITH SLAVE REGULATION

(57) The invention relates to a converter technique and is intended for use on a direct current electric rolling stock. The aim of the invention is to expand the range of voltage regulation at the output of the converter, reduce the installed equipment power and increase the voltage. The device contains an inverter cell consisting of main thyristors 1 and 2, rectifying diodes 3 and 4, autotransformer 5, smoothing reactor 6 and Generator 7 switching voltage pulses. The generator 7 consists of thyristors 8-11 with opposing diodes 12-15 and an oscillating circuit consisting of a reactor 16 and a capacitor 17. The secondary windings 19 and 20 of the pulse transformer 18 are connected to the cathodes of the main thyristors through additional thyristors 22 and 23. To optimize the installed power of the switching voltage pulse generator equipment, the converter can be made with a common voltage and switching pulse generator and containing similar inverter cells 29 and 30. 1 Cp. f-ly, 4 silt

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The invention relates to a conversion technique and is intended for use on an electric current composition of direct current. The aim of the invention is to expand the range of regulation by the yarn at the output of the converter, decrease the installed power of the equipment and increase the CCT.

Figures 2 and 2 show the basic diagrams of a converter with one cell and N additional cells; on and -4 are timing diagrams illustrating its operation in the initial start-up period and in the steady state

The converter (Fig. 1) contains the main thyristors 1 and 2, rectifying diodes 3 and 4, autotransformer 5, smoothing reactor 6, generator 7 of switching voltage pulses, including a thyristor bridge from thyristors 8-11 with counter diodes 12-15 , an oscillating circuit containing a reactor 16 and a capacitor 17 for switching the current of the valves of the thyristor bridge, a pulse transformer 18 with secondary windings 19 and 20, with the terminals of the primary winding 21 connected to the output terminals of the specified bridge, and the secondary windings 19 and 20 included will follow In addition, the converter includes a L-shaped LC filter containing a reactor 24 and a capacitor 25, and a control unit 26 that generates control current pulses in a given time series for unlocking the thyristors of the converter The load 27 of the converter is connected to the midpoint 28 of the autotransferrator 5 through the reactor 6

The elements 1-6, 22 and 23 form a cell 29, and the device in FIG contains N cells, in particular an additional similar cell 30

The outputs of the control unit 26 through the galvanic isolation blocks 31 and 33 are connected with the control transitions of thyristors 1 and 2, blocks 33 and 34 of thyristors 8, 9 and 10, 11, blocks 35 and 36 of thyristors 22 and 23. In the initial interval starting the converter, the control unit 26 supplies the control current pulses only to

thyristors 8, 9, and 10, 11 thyristor bridge control circuits and, with some delay relative to switching voltage pulses, in the control junctions circuit of additional thyristors 22 and 23

After the end of the start-up interval, the control block 26 provides simultaneous unlocking of the thyristors 8, 9 and 22 and 10 11 and 23, respectively, with some advance in relation to the switching voltage pulses, determined by the output voltage or the load current, from the outputs of the block control pulses of control current are received in thyristor 1 and 2 control junction circuits.

In order to optimize the installed power of the switching voltage pulse generator equipment, the converter (Fig. 2) can be made with a common voltage pulse generator and containing N similar inverter cells. The control unit is designed to provide alternating supply of thyristor control current pulses 8, 9 and 10, 11 thyristor bridge of a voltage pulse switching generator and synchronized supply of control pulses to the corresponding main and additional thyristors with a frequency, n times the lower frequency of the control pulses by the valves of the thyristor bridge of the specified generator, with adjustable delay relative to the moment of their supply and shifted among themselves by the angle FH / N.

The converter works as follows.

In the initial start-up period, the thyristors 1 and 1 are locked and the conversion of the DC voltage is carried out by a switching voltage pulse generator, additional thyristors 22 and 23, and rectifying diodes 3 and 4

At time t, a current pulse ivj enters the chain of control transitions of thyristors 8 and 9. At the first output of the switching voltage pulse generator and the primary winding of the transformer 18, a rectangular voltage pulse UK of positive polarity () is formed. The amplitude of this pulse by winding 19 of the transformer 18 increases

is 16-20%. At time tЈ, the current pulse i3 comes to the control transition circuit of the thyristor 22, unlocking of which leads to the injection of a voltage pulse U in the circuit formed by the capacitor 25, inverter valves 8 and 12, the transformer secondary winding 19 18, the thyristor 22, the semi-winding of the autotransformer 5, the reactor 6 and the load 27 In this case, the resulting current flows through the load due to the current in the circuit of the specified circuit and the current induced in the second semi-winding of the autotransformer 5. Through the thyristors 8 and 9 the resultant The current 1 8 of the load on the switching mode icon Since the amplitude of the current pulse 1 of the switching circuit exceeds the maximum value of the load current by more than 2 times, then at time t the current through the valves 8, 12 and 9, 13 changes its direction and the reverse half-wave current flows through diodes 12 and 13. From this point in time, the process of restoring the blocking properties of thyristors 8 and 9 begins. To ensure stable operation of the converter, it is necessary to fulfill the condition that the amplitude of the load current and the duration of the current pulse through Diodes 12 and 13 are longer than the recovery time of the blocking properties of the switching voltage pulse generator thyristors

At time t. the current through the diodes 12 and 13 becomes equal to zero and the voltages on the valves 8, 12 and 9, 13 are restored. At the same time, the thyristors 8 and 9 remain in the locked state. After turning off the diodes 12 and 13, the load current flows through the circuit, which includes the cross section winding of the autotransformer 5, smoothing the reactor 6, load 27 and diode 3.

At time t. current pulse

:) 2

enters the thyristor control junctions 10 and 11, the unlocking of which leads to the appearance of a voltage pulse U of positive polarity at the second generator output. The amplitude of this pulse by the winding 20 of the transformer 18 also increases by 16-20%. Further, when a control current pulse 1uf appears in the thyristor control transition circuit 23, electromagnetic processes in

15

20

they proceed anapogically described.

In the steady state operation of the converter in the initial period — the start-up, the voltage at its output is determined by the expression

Its 2EK, Kzf (Tu - Tzk);

U T5K tl- L3

where E is the voltage of the power source; K and K - transformation ratios

transformers b and 18; f is the inversion frequency; T is the duration of the switching voltage pulses; T - delay time unlocking additional thyristors in relation to the moments of unlocking the inverter thyristors.

The current through the load i due to the large inductance of the reactor 6 25 has ripple-shaped pulsations with a frequency twice the frequency of the switching voltage pulses.

After reducing the delay time of unlocking the thyristors 22 and 23 to zero Zo, the power thyristors 1 and 2 are put into operation, which are opened by current pulses iyg- and i yg

At time t. current pulse i-vig- (fig.Z) enters the thyristor 1 control transition circuit, unlocking which causes current i V) to flow through the circuit formed by capacitor 25, thyristor 1, semi-winding of autotransformer 5, pe 4Q actor 6 and load 27. From this point in time, the voltage in the load circuit is almost equal to the voltage on the capacitor 25.

At time t, a current pulse .gi y enters the thyristor control transition circuit 8, 9, and 22, unlocking which leads to an increase in voltage U 6b |) c by the amount of voltage on the secondary winding 19 of transfer 5Q of the matrix 18. As a result of this, the voltage at the anode of the thyristor 1 becomes negative and it is locked. From this moment on, the process of restoring its locking properties begins, and the load current flows through the circuit formed by capacitor 25, thyristor 8, secondary winding 19 of transformer 18, thyristor 22, semi-winding av otransformatora 5

35

reactor 6 and load 27 At time t. the current through the valves 8 and 12 changes direction and passes from the thyristor 8 to the diode circuit 12. Thus, the current switching process through the thyristors 8 and 9 occurs as described. At the time point, the current through diode 12 becomes zero. From this time point, the voltage U cv (becomes equal to the voltage drop across the diode 3, and the load current flows through the circuit: diode 3, the semi-winding of the autotransformer 5, the actor 6 and the load 27

At the moment of time t, a current control pulse Uu enters the thyristor 2 control junction circuit. Its unlocking causes the load current lug to flow through the circuit formed by capacitor 25, thyristor 2, second semi-winding of autotransformer 5, reactor 6 and load 27 From this point in time the voltage UebK again becomes equal to the voltage on the capacitor 25

At time tg. current impulse "1" enters the thyristor control junctions 10, 11 and 23, the unlocking of which leads to an increase in voltage U YO) (by the voltage on the secondary winding 20 of the transformer 18, and the thyristor 2 locks flows along the loop: capacitor 25, thyristor 10, transformer secondary 18, thyristor 23, second semi-winding of autotransformer 5, reactor 6 and load 27. At time t7, the current through valves 10 and 14 changes direction and passes from thyristor 10 to circuit diode 14 At time The current t through diode 14 becomes equal to zero. From this point in time, the voltage U 8Xx becomes equal to the voltage drop on diode 4 and the load current flows through the circuit: diode 4, the second half-winding of the transformer 5, reactor 6 and load 27. Then the electromagnetic processes in the transducer periodically repeats

The voltage on the primary winding of the UTp autotransformer is rectangular with steps due to the switching voltage pulse UK and pause 1 and 2

in the work of thyristic

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five

0

five

0

five

0

five

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five

Claims (1)

Invention Formula one . A constant-voltage constant-voltage constant-voltage converter containing an input filter connected to an inverter cell comprising two thyristors connected by anodes to a positive input terminal, and cathodes to diode cathodes and a transformer winding, a switching voltage pulse generator, connected to the minus input terminal and consisting of a thyristor bridge with the primary winding of the switching transformer in the diagonal of alternating current and a resonant LC circuit, and the load circuit is It is connected to a negative input terminal, as well as a control unit, which is characterized by the fact that, in order to expand the range of output voltage regulation, reduce equipment installed power and increase efficiency, the inverter cell is equipped with two additional thyristors, and the switching transformer is made with two secondary windings, each of which is connected to the corresponding AC output of the pulse generator bridge and connected through an additional thyristor to the cathodes of the thyristors of the inverter unit iki, the transformer winding of which is an autotransformer connected with an average output to the load circuit, and the anodes of the cell diodes are connected to the negative input output, and the control unit is designed to provide a synchronized supply of control pulses to the corresponding main and switching thyristors, as well as the supply of pulses - full-line thyristors with adjustable delay relative to the supply of control pulses to the switching thyristors 2 The converter according to claim 1, T is characterized in that it is equipped with N additional inverter cells, where N is an integer number, and the control unit is designed to supply control pulses to the main thyristors shifted by an angle of fr / N . t SN s. s Yg Jl § c- u cr VO LT1 Oh