SU436429A1 - DEVICE FOR PULSE-PHASE CONTROL OF T-PHASE VENTIAL CONVERTER - Google Patents

Description

I

The known device for phase-to-phase control of a phase-converter valve comprises a regulating voltage source, a power source and m control channels, each of which has a switch on the transistor controlled from a t-phase clock transformer, the common point of the secondary winding of which is connected through a resistor with an emitter of the transistor and with one of the output terminals of the voltage regulating source, a phase shifting element, and a pulse shaper.

Such a device is quite complicated and has low reliability.

The purpose of the invention is to simplify the device and increase the reliability of its operation. This is achieved by the fact that in the proposed device the phase-shifting element is designed as a transistor. Blocking generator with a transformer on a core with a rectangular hysteresis loop with control windings, readout in the collector circuit of the transistor and output, with the end of the control winding connected to the collector of the switch transistor, beginning - to the second terminal of the regulating voltage source, the output winding is connected to the control circuit of the additional transistor switch, the output of which is connected to the input form The pulse generator, and the end of the read winding is connected to one of the power supply terminals, the second clip of which is connected to the common point of the switch transistors. A choke is connected between the common point of the secondary winding of the clock transformer and the resistor to increase the symmetry of the control pulses and reduce the power of the clock source.

To ensure steady operation of the converter to inductive AC load and to avoid self-oscillations of the valve-driven electric drive.

direct current in the mode of intermittent currents at small control angles the pulse shaper is made in the form of a pulse transformer, the control winding of which is connected to the control transition of the converter valve, the primary winding through the limiting element and the diode in the non-conducting direction is connected in parallel to the valve, and the secondary winding through the diode is connected in parallel to the emitter-collector

circuit additional transistor key. The pulse shaper can be made in the form of a pulse transformer and a chain of series-connected capacitor, resistor and diode connected in parallel to the emitter-collector

circuit additional transistor switch, and the secondary winding of the transformer is connected in parallel to the resistor and the diode.

FIG. 1 shows the scheme of the proposed device; in fig. 2 and 3 are embodiments of a pulse former; in fig. 4 is a diagram of the operation of the device.

-The device for pulse-phase control consists of a valve switch with a synchronizing transformer TFC, TCiH TC2 transistors, a choke D and a current limiting resistor R; TI and T2 transistor blocking generators and Tpi and Tr2 transformers on cores with a rectangular hysteresis loop; keys according to the common emitter circuit on Tz and T4 transistors, pulse formers Oi and F2, TS and T transistor input amplifiers with an output stage according to the emitter follower circuit and a common power source U.

The device works as follows.

At the moment .ti (fig. 4) unlocking the synchronization transistor TCi of the gate switch (fig. 1), the output voltage VDLIX of the DC amplifier, i.e., the voltage between the positive source, is applied to the control winding of the op-amp of the phase-shifting blocking generator on the TI transistor. power supply Uu and emitter of the output transistor TS amplifier. Under the action of this induction voltage B in the transformer core, Tpi begins to change from the saturation state of the t-BS to -j-Sg, never reaching the state.

The magnetization reversal of the core by the voltage of ALARM lasts for a time interval tz when the transistor TS is opened, i.e. during one half period of the supply voltage. In this case, the induction increment in the core of the transformer Tpi is

T

T

(one)

Wys

where T is the period of the supply voltage; Wy - the number of turns of the control winding

OU

5 - core section; output is the output voltage of the amplifier.

t

at time tz - transistor TC,

BUT

locked up. The current in the recording winding drops to zero. In connection with a sharp drop in current in the control winding of an op-amp, an electromotive force is induced in all the windings of the Tpi transformer. In this case, the polarity of this emf. is such that the transistor T of the phase-shifting blocking generator is unlocked, and a current from the power source f / n- starts to flow through the winding of the OCi. At the same time, the transistor Tz Klyu.cha is unlocked. Under the action of the voltage t / n, the core begins to re-magnetize to its original state: --fig. In the process of magnetization reversal in the coil of a positive feedback, the nOCi induces an emf that maintains the open transistor TI, and the voltage of the output coil of the OBi blocking generator maintains the transistor Tz of the switch in the open state.

When the core of the Tpi transformer is saturated (reversal) to the initial state (-5 s), emf. on the feedback winding, the POS is reduced, which leads to a decrease in the collector current and the emergence of a positive potential on the basis of the transistors T and T3 and their fast locking. The collector potential of the transistor Tz falls. Differential capacitance voltage drop across capacitance Ci triggers F1 pulse generator.

Since the change in induction is in the interval when the transistor TSb is open and in the interval 2, h. when the transistor T is open, the same, i.e.

1D5,1- | D5e |, (2)

Vvco

where tc, is the time of magnetization reversal of the transformer core from TO-BS, s is the number of windings of the OS), then

2

 cf / n

(3) W-, S

From the last equality, we obtain an expression for the duration tc of the interval t, t

 .W

(4) U Un

Multiplying the right and left sides of equality (4) by the value of the angular frequency of the network, we obtain the phase shift of the control pulse of the imager Φ in electric degrees.

° a - v, x.

glad -

(7.g - Wff ---. I7v

t / n

 180 -.- e. degrees (5)

Un

W,

If wy we then

and 7g - happy: 180 e. hail. (6)

Unun

From (6) it follows that when the output voltage of the amplifier f / output changes from O to Un, the phase of the control pulses will change from O to 180 el. -hail. FIG. 4 shows a work diagram.

pulse-phase control devices:

Its steering angle is 90 el. hail.

i

and t / o, "with 180 EL. Hail.

If, in the interval when the transistor TCi is open, the voltage Uvih varies in magnitude, the control angle will be determined by the average, over the interval i, 2, the value of the output voltage.

A significant advantage of the proposed device is that it is simpler known, contains only one source of direct current, common to phase-shifting blocking generators, an amplifier and a pulse shaper. In order to increase the reliability of operation in series with the current limiting resistor R of the valve switch, a smoothing choke D is included, which ensures the flow of rectangular current pulses in the bases of the TC and TC2 transistors and eliminates the switching switch transistors in proportional mode.

A choke provides a well-smoothed voltage across the resistor R, which is applied to the bases of the transistors TI and Tr of the blocking oscillators as a bias voltage. In addition, the flow of the bias current from the point of connection between the droplets D and the resistor R over the windings nOCi and POS2 contributes to the increase in the sensitivity of the blocking generators to the control voltage.

To reduce the power of the power source and ensure stable operation of the valve converter for inductive load, especially with a variable power factor during operation and to avoid self-oscillations of the DC valve drive at small control angles in the discontinuous current mode, instead of blocking the generator of the pulse driver, it is necessary to turn on pulse transformer, as shown in FIG. 2

As long as the core of the phase-shifting blocking generator oscillates, the secondary winding of the pulse transformer ITp1 is shorted by the transistor Ty and in the control winding T, - connected to the control transition of the valve, for example, a thyristor, the voltage is absent. When the transistor Tu is locked, the voltage of the thyristor anode-cathode is transformed into a control winding and unlocks the thyristor.

If at the moment of time (corresponding to the angle ap) determined by the output voltage (the thyristor anode output is negative with respect to the cathode, which can occur in a DC drive, the control pulse arrives at the control electrode of the thyristor at the instant of equality ed motor and mains voltage. This eliminates the misfiring of valves and self-oscillations of the electric drive.

FIG. 3 shows a simplified version of the device. When the transistor T of the phase-shifting device is locked, the primary winding of the pulse transformer HTpi is connected to the power source through a capacitor and the control pulse is sent to the control electrode.

Subject invention

Claims (4)

1. A device for pulse-phase control of a t-phase valve converter containing a regulating voltage source, a power source and m control channels, each of which has a switch on a transistor controlled from a t-phase clock transformer, the common point of the secondary winding of which connected through a resistor to the emitter of the transistor and to one of the output terminals of the regulating voltage source, a phase-shifting element and a pulse shaper, characterized in that, in order to simplify Realizing and increasing the reliability of its operation, the phase-shifting element is designed as a transistor blocking generator with a transformer on the core with a rectangular hysteresis loop with control windings, readout in the collector circuit of the transistor and output, with the end of the control winding connected to the collector switch transistor, start to the second terminal of the regulating voltage source, the output winding is connected to the control circuit of the additional transistor switch, the output of which is connected to the input the pulse driver, and the end of the read winding is connected to one of the power supply terminals, the second terminal of which is connected to the common point of the switch transistors. 2. A device according to claim 1, characterized in that, in order to increase the symmetry of the control pulses and reduce the power of the synchronizing voltage source, a choke is connected between the common point of the secondary winding of the synchronizing transformer and the resistor. 3. The device according to PP. 1 and 2, characterized in that, in order to ensure stable operation of the valve converter on inductive load of alternating current and exclusion of self-oscillations of a DC electric drive motor in the mode of intermittent currents at small control angles, the pulse shaper is made in A pulse transformer, the control winding of which is connected to the control transition of the converter valve, the primary winding through the limiting element and the diode in the nonconductive direction is connected in parallel to the valve, and the secondary winding through the diode is connected in parallel to the emitter-collector circuit of the additional transistor switch. 4. The device according to PP. 1 and 2, characterized in that the pulse shaper is designed as a pulse transformer and a chain of a series-connected capacitor, resistor and diode connected in parallel to the emitter-collector circuit of an additional transistor switch, and the secondary winding of the transformer is connected in parallel with the resistor and diode. The priority according to claim. Is calculated from 10.03,72. - Un ig2 -Up o 4h -TO G-, + Un Oh ig.d