SU1259448A1 - Method of controlling bridge converter - Google Patents

Abstract

The invention relates to converter technology and can be used in precision width-controlled electric drives of CNC machines and makes it possible to improve the quality of regulation. The device contains thyristors 1-6 of the bridge connected to the windings of the power transformer (T) 9. Zero thyristors (NT) 7, 8 are connected to the zero point of the star winding T 9. At the moment of turning on the NT 7 or 8, the second additional pulses are simultaneously applied to switching on the thyristors of the bridge. &Amp; amp converter S o s (O S

Description

1259448

It works both in continuous mode, due to a decrease in the current, and in the intermittent-current mode of the discontinuous current. that current. Quality is regulated - 3 Il.

The invention relates to a converter technique, in particular, to methods of controlling static converters, and can be used in precision latitude-controlled electric drives of CNC machines.

The purpose of the invention is to improve the quality of regulation by reducing the area of the dead current.

Fig. 1 is a circuit diagram of a device implementing the proposed method; in fig. 2 - diagrams of output voltages of the converter; in fig. 3 shows timing diagrams of valve control pulses at different control angles.

A device for carrying out the proposed method comprises gates 1-6 of the bridge (thyristors); zero valves 7 and 8 (thyristors); power transformer 9; load 10.

FIG. 2 are marked: linear voltages 11-16 of the transformer secondary winding (11, 13 and 15, respectively AV; Sun; CA — direct and 12, 14, and 16 — AC, VA; SV; reverse sequences), phase voltage 17-22 (17, 19, and 21, respectively; a; 6; o, direct and 18, 20, and 22, respectively, c; q; g reverse sequences), 23–35 times considered during the operation of the bridge converter, pulses 36-43 control thyristors 1-8, respectively.

The second additional pulses in the diagrams (Fig. 3) are shaded. At times 24 and 30, the second additional pulses coincide with the first additional ones and are not shaded.

When the voltage changes from the maximum value to zero, the bridge converter is controlled

in two stages. In the first stage, the angle

control of the main impulses is not pre- / II

extends relative to the natural switching point of the thyristors. In this case, the control angle of the second additional pulses is fixed and

1G is equal to g. If the corner control corner 7

no more than t pulses, only thyristors of the bridge work (interval 23-24 time). In this case, during the conduction interval of each thyristor of the bridge, two impulses (main and first additional) are applied to the control electrodes of the thyristor, shifted relative to

each other on - (fig. 2). Second

additional pulses are formed

IT with control angle j and influence

the work of the converter is not provided. When the valve control angle is mine.

This one doesn’t, but not more, the circuit works similarly, with the only difference that now the second additional pulses affect the operation of the converter, including bridge valves and zero valves. Let, for example, at time 27 (FIG. 2) thyristors 3 and 2 are open.

At time 28

an impulse to open the zero valve 7, which is simultaneously applied to the thyristor 2 as the second additional impulse. As a result of unlocking the valve 7, the valve 3 closes and the output voltage of the converter changes in accordance with the phase 20 (phase A, Fig. 2). Then at the time 29 the main pulse is formed on the thyristor 5. The same pulse arrives as the first additional on thyristor

31

2. Accordingly, the output voltage of the converter is then changed along curve 15 (CA, Fig. 2). This process is repeated further, as a result of which the phase and linear voltages act on the load.

In the second control stage, the control angle of the main pulses is more

7

". Impulses of management of zero veins -

tile shape according to

ti odg -. Let thyristors 6 and 3 be open (time instant 31, - fig. 2). At time 32, a control pulse is generated on the thyristor 8. This same pulse, as the second additional, goes to thyristor 3. As a result, a phase voltage is applied to the load across the thyristor circuit 3 and 8 (Fig. 1). Then a main pulse is formed on the thyristor 2. The same pulse in,. As the first additional, the thyristor 3 is supplied. Since the second additional pulses are simultaneously applied at the moment of switching on the zero valves, the converter operates both in the continuous current mode and in the discontinuous current mode, and compared to the known solutions, the proposed method allows increasing quality of regulation

five

Q

50

five

484

by reducing the discontinuous current area.

Claims (1)

Invention Formula The method of control of the bridge converter, which consists in that the control and electrodes of the bridge gates supply the main and additional control pulses that are measured relative to each other. an angle equal to r, characterized in that, in order to improve the quality of regulation by reducing the area of the direct current, second additional pulses are fed to the control electrodes of the bridge gates and zero gates, the control angle of which is fixed at 7  when changing the angle of control of the main controls of their pulses from l to, and at the control angles of the main control pulses more T "Second additional pulses form with the angle of control ot-o according to oto |, where ci is the angle of control of the main valves. ff / L7 / YY Editor A.Shishkin Compiled by G. Mytsyk Tehred L. Serdyukova Order 5136/56 Circulation 631- Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 F1 / d Proofreader M.Maksimishinets