SU699649A1 - Device for switching-over stages of multi-bridge thyristorized converter - Google Patents

Description

one

The invention relates to devices for controlling single-stage thyristor single-phase current converters with smooth non-contact phase-zone regulation of rectified and inverted voltages and can be used in electric drives with multi-stage voltage regulation on the load, mainly on electric transport.

A device is known for switching the steps of a multi-bridge static converter comprising phase-shifting elements; pulse phase distributors, angle meter, commutators, logical elements of coincidence, OR assembly element, differential elements, diode limiters and triggers with separate start 1.

The drawback of the device is that the operation and release of the switch can occur at the same angle of control, as a result of which the return coefficient of the switch remains constant and equal to one, which can lead to a change in the operation of the converter at the moment of switching its steps.

The closest in technical essence to the proposed invention is a device containing a time delay element, a driver of the reference pulses at the beginning of the half period of the supply voltage converter, as well as phase shifting

0, the elements of the respective converter stages, the outputs of each of which are connected to the inputs of the coincidence elements, and the outputs of those of the above-mentioned coincidence elements,

5 to the second inputs of which one of the trigger outputs with separate start is connected, connected via the Phase-shifting pulse distributor and the amplifier unit with

0 control electrodes of the power thyristors of the converter 2.

A disadvantage of the known device is the complexity and low immunity due to the presence of a trigger switch with a countable start in the circuit.

The purpose of the invention is to simplify the design and increase the noise immunity.

The goal is achieved by the fact that the known device is equipped with OR-NOT logical elements, one of which is connected between the output of the reference pulse generator and the input of the Toggle coincidence element, to the second INPUT of which the output of the first-stage converter is connected and the other element is OR-NN; connected between the output of the phase-shifting element of the first stage and the input of that element of coincidence, to the second input of which, through the time delay element, the output of the said driver is connected. reference pulses, and the outputs of these two elements of coincidence are connected to the trigger trigger inputs with separate start.

FIG. 1 is a schematic block diagram of the device described; in fig. 2 shows time diagrams of the voltages at the outputs of the elements of the device before switching; the converter from the first stage to the second in FIG. Figure 3 shows time diagrams of the voltages at the outputs of the elements of the device after switching the converter from the first stage to the second.

The device for switching the steps of the multi-bridge thyristor converter contains —former of reference pulses 1, element OR — NOT 2, element of coincidence 3, phase-shifting element 4, element of time delay 5, element of coincidence 6, element OR-HE 7, trigger 8, element 9, a phase shifting element 10, a coincidence element 11, a distributor 12 pulses of phase shifting elements, an amplifier unit 13, a converter 14 and a power transformer 15.

All elements of the proposed device can be implemented on integrated circuits.

The device works as follows.

At the beginning of each half-period of the power supply to the voltage converter, the driver 1 forms a reference pulse Uon with the phase. FIG. 2 and 3); which arrives simultaneously to the input of the element OR-NOT 2 and to the input of the element of the time delay 5. At the output of the element OR-NOT 2 receive., an inverted reference pulse UQ, see fig. 2 and 3) which is fed to one of the outputs of the coincidence element 3, the second input of the element of coincidence 3 receives the pulse Upen (cM.) Of the figure, phase-controlled oper 1. 2 and 3).

The Uper-i pulse is formed by the first-stage phase-shifting element 4 of the converter, and the phase-shifting element 4 converts the control voltage into pulses Up. rectangular shape. With an increase in the voltage of the control, the phase of the pulse Upeg changes ets oTtipe, r 180 electrical degrees to ac, reg o electrical degrees, as the phase-shifting elements 4 and 10 have a reverse phase response.

As long as the inverted reference pulse and (.j from the output of the element OR NONE 2 and the pulse Uper-iC of the output of the phase-shifting element 4 will be fed to the inputs of the coincidence element

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3 simultaneously, the signal U of FIG. 2) at its output, and, consequently, at one of the inputs of trigger 8 with separate start will be absent.

The delayed reference pulse U (jpj (see Figs. 2 and 3)) having the oCope phase arrives at one of the inputs of the coincidence element 6, which is removed from the output of the time delay element 5 (see Fig. 1). phase shifting element

4 and inverted by means of an element OR-NOT 7 (see - fig. 1) pulse.

(see Fig. 2). At the simultaneous presence at the inputs of a matching element 6 a pulse of the output of a time delay element 5 and a pulse Uper from the output of an OR-NOT 7 element at the output of a matching element 6 (see Fig. 1), a signal is generated. 2). The output element signal UCOBHU 6 coincides with the second input of the trigger 8 with separate start, keeping it in such a state that the permitting signal is removed from one of its outputs (see Fig. 2) at one of the element inputs. coincidence 9 (see Fig. 1), and from the other output of the trigger 8, the inhibit signal U-pp4 (see Fig. 2) is output to one of the inputs of the coincidence element 11 (see Fig. 1). At the same time, the pulse and peri from the output of the phase-shifting element 4 through the open coincidence element 9, the distributor 12 pulses of the phase-shifting elements block amplifier 13 enters the first stage of the converter 14, adjusting the valve opening phase in the arms of this stage. The pulse Uper2C of the output of the phase-shifting element 10 through the closed element of the coincidence 11 and the second stage of the converter does not pass (see Fig. 1).

As the voltage of the phase-to-p control voltage increases, the pulse Uperi from the output of the phase-shifting element 4 of the first stage of the converter decreases. However, while the inequality is fulfilled (see FIG. 2)

Claims (2)

1. USSR Author's Certificate No. 440282, class; H 02 R 13/16, 1974. 2. USSR author's certificate number 440283, cl. H 02 R 13/16, 1974. R S5