SU1347137A1 - Method of relay control of three-phase thyristor a.c.-to-d.c.voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used to control the excitation current of electric machines. The aim of the invention is to increase speed. In this method, a difference signal between the actual current of the converter and the specified current is determined. With a positive sign of the differential signal, control pulses are applied to the thyristors, and if negative, the control pulses are shifted to the lagging side, and then they are fed to the thyristors. 2 Il. (L SA: it SAD |

Description

13471372

The invention relates to an electro-phase transformer 13, input

technology - namely, the power converting leads connected to the source 1,

to the usable technique, which is used as the output, to the corresponding inputs for controlling the excitation current of the switch’s

electric cars, for example, in r-on electronic keys 14-19. Control diesel-electric driving LEDs 20-25 optocouplers

direct current self-propelled device 2-7 connectors in the form of three (powerful pneumowheel and caterpillar phase bridge, on the code of which podtransport and earthmoving transport-- IQ includes a resistor 26, and the input pins

special matins). connected to the corresponding weekend

The aim of the invention is to raise the pins of the switch. Managers

control speed. The electrodes of the keys 14, 16 and 18 are combined in accordance with the relay control method and are connected to the output of the company by a three-phase thyristor converter. The control electrodes of the keys, the ac voltage detector B15, 17, and 19, also combine the subconstant shift of the switching impulse-connection to the output of the HE element 12. at 120 electr., In the direction of the back-resistor 26, to limit the negative The sign of the time-current flowing through the LEDs of the nostral signal and their supply to the pack- 20 20-25.

Ravl Jupshe Thyristor Electrodes Allowed - Shaded Temporal Area

The transducer from diagrams (Fig. 2b) corresponds to the fixed state of the rectifier-to-open state of the thyristors 2-7 of the sleeping mode, in which it was responsible.

before that, in a fixed state of 25, the device operates as follows in an inverter mode. Under the influence of

the back EMF of the inverter, the value of which is suppose at the initial moment

This absolute value is equal in time to the signal U (Fig. 2) of setting the voltage catch of the converter over the amplitude of the signal Ug of the sensor 9 of the rectifying mode, and a current occurs (Fig. 1). As a result of comparison

forced fall of the current of the converted signals in the comparator 11

the body in a shorter time at its output appears positive. Thus, due to a decrease in the signal U, which closes the beak of the task to start the switch 14, 16 and 18 of the switch. At the output, the reduction of the converter current, element 12, the signal AND inverts the speed of the control of the conversion, and the control output of the switch, receives a negative (or FIG. 1, principal left) signal, resulting in a implementations 15, 17, and 19 remain open; relay control methods; 2. Under the action of a positive fig. 2, time diagrams of the voltage of the U phase c and the negative scientific research institute on the device elements. Voltage U, phase b (Fig 2a) trans The device contains a source 1 of the transformer 13 current flows across the circuit: three-phase voltage, to the terminals of co-18, 24, 26, 23, 16, as a result of the second, the leads of alternating current flow through the LEDs 24 and 23 of the current of the three-phase bridge of the optocoupler tiri-optron thyristors 6 and 5 of the 2- 7, To the terminals of a constant current (fig 28), the linear voltage ka of a three-phase thyristor bridge through the thyristors 5 and 6 is applied is connected to the active inductive-load 8 through the load 8 nachi- Booting 8, v apparatus also comprises naet leak current. The current sensor 9 proportional to the load current circuit 8 changes the signal Ug of the converter current, the current form sensor 9, At time t, the reference signal world 10, the output voltage U of phase a becomes more house connected to one the input is com-positive than the voltage Uc of the farator 11, to the second input of which c, as a result, the output of the current sensor 9 is connected, the ele-LED 20 is connected to the circuit: 14, 20, 26, 23, HE 12, the input connected to you-16, the LED 24 is closed under the course of the comparator 11, the driver action about -negative voltage pulses, made as a tri- (Uc-Uo), accordingly opened

313

The optocoupler thyristor 2 (Fig. 25), and the thyristor 6 is locked during its operation. natural switching (switching process is not shown), the load 8 is applied to the linear voltage (U.-

l

source 1, under the action of which the load current continues to increase. Next until time t. switching processes of LEDs and optocoupler thyristors proceed in a manner similar to that described. Thus, in the time interval when the U-reference signal exceeds the current sensor signal Ug, the thyristor bridge operates in an uncontrolled (diode) rectifying mode, and the rectified voltage U is applied to the load 8 (Fig.Pa) . At time t, the signal U becomes larger than the signal U, g, the signal C, at the output, the comparator from the positive becomes negative (or zero), - at the output of the element NOT 12, the signal and Inverts, so that the keys -14, 16 and 18 open , and the keys 15, 17 and 19 are closed, the state of the keys becomes opposite, shown in FIG. 1, As a result of the switching made, the current pulses through the control LEDs begin to flow with a shift of 120 zl. hail. According to this converter control algorithm, it must be transferred to the inverter mode, but until natural switching of thyristors 3 and 6, which were previously carried out in Fig. 28}, tj, the output voltage of the converter retains a positive sign. Immediately after the time tj, the LEDs 21 and 24 conduct current through the circuit: 19, 24, 26, 21, 1.5, keeping the thyristors 3 and 6 in the open state. The converter is switched to the inverter mode, the voltage at its output becomes negative. which causes the load current 8 to start to drop. At time t, the current from the LED 21 is transferred to the LED 23, the optocoupler 5 is opened, the thyristor 3 is naturally switched, the converter remains operating in dependent inversion mode. Further switching processes proceed in a similar way.

Thus, in the time interval when the reference signal U is less than the current sensor signal Ug, the pulses

374

switch-ons are supplied to thyristor control electrodes with a shift of 120 e, degrees. in the direction of lag, and the converter is switched to the inversion mode.

The average voltage of the dependent inverter is

Tlli

Ud, HH6 1 J E Sinu3t (c0t)

- 3 r 23G

where E is the phase voltage of source 1 which is half the rectified

3/6 voltage - E.

In this case, the angle of the reserve for natural switching of thyristors is not more than 60 el, degrees.

Under the action of the inverter's back EMF, the current in the load 8 decreases, tending to a steady negative value of -4 (where Rg is the active resistance & load 8),

As a result, the current reaches a certain setpoint in the direction of decreasing in a shorter period of time (FIG. 2o, time interval after t, solid Uq line) than in known devices (ibid, dotted line Ug), and therefore, the proposed method control has a higher speed than the known.

Claims (1)

Invention Formula The method of relay control of a three-phase thyristor converter of alternating voltage into a constant, consisting in that they form a signal for setting the current of the converter, measure the instantaneous value of the actual load current of the converter, subtract the value of the actual load current of the converter from the value of the signal for setting the current of the converter, receive a difference signal, determine the sign of this differential signal, form the control thyristor pulses of the converter, with a positive sign of the differential signal control signals are applied to the thyristors of the converter, which is different with the fact that, in order to improve performance, with a negative sign of the difference signal, the pulses 13471376 thyristor controls are shifted to the supply voltage and fed to the lagging side by 120 e.h. from the resistor transducer. Uam m) P "1 Editor O. Golovach Compiled by E. Kadinkin Tehred L. Oliynyk Proofreader B. Butt ha Order 5124/49 Circulation 658 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 yl.g