SU1644327A1 - Controlled ac-to-dc voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and is intended for use mainly on electric rolling stock of AC railways. The purpose of the invention is to simplify and increase reliability. Due to the use of two single valve arms 4,5 connected to the beginning and end of the first sectioned secondary winding of a transformer 9 in a regulated converter, and by cathodes respectively to the end and beginning of the second winding, as well as a control method providing alternation of power supply connected to the load of sections 11-14 of the secondary windings of the transformer, a reduction in the installed power of the thyristors is achieved, and the number of amplifiers-pulse drivers is reduced. 3 il. yo

Description

The invention relates to electrical engineering and is intended for use mainly on electric rolling stock of AC railways. The purpose of the invention is to simplify and eat. reliability

Fig. 1 shows a circuit diagram of an adjustable converter; Figures 2 and 3 are time diagrams of its operation, reflecting the nature of the change in voltages and currents in the various elements of the circuit, respectively, in the current and inverter modes of its operation.

The adjustable rectifier contains controllable valve arms 1-8, a transformer 9 with a primary 10, a first with sections 11, 12, and a second with sections 13, 14 and secondary windings, a load circuit 15 consisting of a smoothing reactor 16 of the current (pulsating) current 17, excitation winding 18. To the same electrodes of the anode group of valve arms 1-3 and the cathode group of valve arms 4.-7 are connected a load 15. The beginning, end and middle terminal of the first secondary winding 1-3 shoulders, with The corresponding conclusions of the second secondary winding are to the anodes of the 6-8 cathode arm group.

Single valve shoulders 4.5 anodes connected to the beginning and end of the first winding, and the cathodes, respectively, to the end and the beginning of the second winding.

In Figures 2 and 3, the following notation is used:

U2 is the voltage of the secondary windings of the transformer;

i T1 -I T8 - current pulses on the valve arms 1-8;

UB, UHHB voltage on the load in rectifying and inverter modes. The numbers denote the number of valve shoulders, according to figure 1.

The converter in rectifying mode operates as follows (see Fig. 2).

In the first control zone, when opening the valve arms 2, 4, 6 (the polarity of the voltage on the secondary windings is such that under the action of the applied voltage, the current flows from the beginning of the windings to the end) at the end of the semi-peridous valve valve 1, commuting 2 and arm 8 switching from 6. When the voltage is changed on the secondary windings of the transformer by opening the valve shoulder 5, the shoulder 4 is locked and a buffer circuit is created to flow

load current across valve arms 1.5 and 8. Phase control is performed by valve shoulder 7. At the end of the half-period, valve arms 6, 7 and 3 are switched from 1.

and when changing the polarity of the supply voltage, the valve arms 4 to 5 commute. In this half-period, the buffer circuit is created by the valve arms 3, 4 and 6, and the phase control is performed by the ventilation arm 2. Thus, in the first control zone, the voltage on the load varies smoothly from 0 to 0.25 full, while in one half period the load current flows through section 12 of the first

5 secondary winding, and in the other - section 14 of the second secondary winding of the transformer.

In the second zone, when the valve arms 2, 4, 6 are fully opened and the phase regulation by the arms 1, the voltage of section 11 is smoothly added to the rectified voltage of section 12. In the other half, the valve arms 1, 5, 7 fully open and the phase regulation shoulder 6 to

5, the voltage of section 14 is added smoothly to the voltage of section 13. At the end of the first half period, switching from shoulder 6 to 8, at the end of the other from arm 1 to 3. Thus, in the second control zone, the voltage on the load changes smoothly from 0.25 to 0.5 full.

In the third zone of regulation in one half period with open valve arms 1, 4, 6 and phase control of arm 7 to

5, the voltage of section 13 is added to the rectified voltage of sections 11, 12. At the end of the half period, arm 8 switches to 7, when changing the polarity of the supply voltage by opening the valve arm 5

0 is locked 4, then the opening of the arm 6 is locked 8. The phase control is performed by the valve shoulder 2. In the second half-period, the voltage of section 11 is smoothly added to the rectified voltage of sections 13, 14. At the end of the half-period, the valve shoulder 3 switches from 2. Thus, in zone III, the voltage regulation on the load varies from 0.5 to 0.75 full.

0 In the fourth zone with fully open valve arms 1, 4, 7 and phase control of arm 8 (in the second half-period, respectively, with open valve arms 2, 5, 6 and phase control

5 arm 3) the voltage across the load varies from 0.75 full value to full.

The algorithm of the inverter in the inversion mode is similar to the rectifier mode. The difference lies in the fact that the corresponding valve arms are open mainly in the nonconductive half period. The voltage forms of the inverter in the control zones with indication of the numbers of open valve arms are shown in FIG.

The proposed converter is quite simple while maintaining all operating parameters (voltage control range, number of zones, etc.).

Simplifying the device increases its reliability in operation when using valves with equivalent fail-safe performance indicators, simplifies maintenance, reduces labor costs and running costs.

Claims (1)

Invention Formula Adjustable AC voltage to DC converter containing a transformer with a primary winding connected to the input terminals for connecting a power source and two secondary windings, each of which is made in the form of two sections, as well as united by the same electrodes in the anode and cathode groups controlled valve arms and block control, with the beginning, end and middle terminal of the first secondary winding connected to the cathodes of the corresponding valve arms of the anode group, similar conclusions of the second winding to the corresponding anodes of the cathode group of valve arms, and common connection points of like electrodes of the specified groups of valve arms are connected respectively to the first and second output terminals for connecting a load circuit, characterized in that, in order to simplify and increase reliability, two single valve arms are additionally introduced into it The anodes are connected respectively to the beginning and end of the first secondary winding, and the cathodes are connected to the same terminals of the second winding, and the control unit is arranged to alternate the connection of the secondary winding sections of the transformer to the load circuit through half-periods of the supply voltage, and each half-period with a transition to a higher potential of the rectified voltage in all zones of the zone-phase regulation of the rectified voltage, except the last, ig Chinw (Uzona) W (Shzon) Uun8 & zolo) UUH§ 11zone) Fig.Z