SU1001428A2 - Single-channel device for control of gate-type converter with cathode group of thyristors - Google Patents

Description

The invention relates to electrical engineering.

According to the main author. St. 862349 single-channel single-channel device for controlling a thyristor valve converter with a cathode group containing a diode distributor of pulses, a control voltage source, a relay element with an output key, a load current sensor, the output of which is connected to the input of the relay element via a control voltage source, and a key A relay element is included in the neutral wire of the diode pulse distributor.

A disadvantage of the known device is that it does not provide speed when testing a stepped control signal to reduce the current with an inductive load.

The purpose of the invention is to expand the functionality by reducing the transition time during inductive load.

This goal is achieved by the fact that a single-channel device for controlling a valve converter with a cathodic thyristor group is equipped with an inverter one. diode distributor, additional) key of the relay element, and the relay element inverse input, the additional key of the relay element connected to the neutral conductor of the inverter diode distribution, tel, and its control input is connected to the inverse output of the radio element. .

FIG. 1 is a schematic diagram of the proposed device; in fig. 2 shows an example of a relay element.

15

A single-channel device for controlling a valve converter with a cathode group of thyristors contains a current sensor 1, for which the measuring

20 shunt connected in series with the load 2 valve converter. The output of current sensor 1 is connected to the input of relay element 3 in series with the source 4 of control voltage. The relay element 3 is a series-connected DC amplifier 5, Schmidt trigger 6, a switch 7 with a contact 8. A contact 8 is inserted into the neutral conductor of a diode distributor 9 pulses. The diode distributor 9 pulses contains a three-phase transformer 10 and diodes 11–13. The windings of the transformer 10 are connected to a star with zero wire and are connected to the power grid and the secondary ones are connected to the control electrodes of the corresponding thyristors 14-16 . The zero point of the secondary windings through the limiting resistor 17 and the contact 8 are connected to the cathodes of the thyristors 14 - 16 of the valve converter. Inverter diode distributor 18 pulses consists of diodes 19-21 and a transformer 10, the secondary windings of which are connected as follows; the end of the phase C winding with the beginning of the phase Winding phase; the end of the phase B winding through the diode 19 to the control electrode of the thyristor 14; the windings of phase B and A are similar to that of the diode 20 to the thyristor 15, similar to phase A and C through the diode 21 to the thyristor 16 The zero point of the secondary winding through the limiting resistor 122 and the switch 23 are connected to the cathodes of the thyristors 14 through a 16-valve converter. The device works as follows. To the input of the relay element 3 from the source 4 of the control voltage is supplied the control voltage U. The key 8 of the relay element 3 is closed, as condition I-K17D is satisfied where the output voltage of the sensor 1 of the load current 2; 2 L is the width of the hysteresis loop of the relay element 3}. It is chosen smaller than the amplitude of the pulsations; UQC voltage sensor 1 load current 2. The value of KI is equal to O at the initial moment of time. A pulse distributor 9 assembled at a transformer 10 provides a control signal to that of thyristors 14-16, at the anode of which the highest potential. If the highest potential is on the thyristor anode 14, then the control signal passes through the circuit: the end of the winding of the phases A of the distributor 9 pulses, the diode 11, the control electrode of the thyristor thyristor cathode 14, the closed switch 8 limiting resistor 17, the common point of the diode distributor. Circuit 14 opens and voltage A is applied to load 2. Current I of load 2 under the action of voltage Phasn A increases. The voltage from current sensor 1 increases and when -KK-D the relay element 3 is triggered and opens its key 8, relieves the control voltage from the thyristor 14. In this case, the switch 23 of the relay element 3 closes and the inverter distributor 18 pulses gives a control signal on one of the thyristors 14 - 16, on the anode of which the most negative potential. This thyristor cannot ignite at a given time. Therefore, the thyristor 14 continues to conduct. When it reaches its maximum, the load current 2 and, accordingly, the voltage of the current sensor 1 begin to decrease under the effect of a decreasing phase A voltage. When the U-KI TD condition is fulfilled, the relay element 3, closes key 8 and opens key 23 .. A diode pulse distributor 9 supplies a control signal to the thyristor 15, the anode of which is at the highest potential along the circuit: the end of the phase B winding of the distributor 9, diode 12, controlled gate electrode 15 of the thyristor, the cathode of the thyristor 15, the closed switch 8, limiting resistor 17, the total point of the diode of the distributor 9. The thyristor 15 is opened and the load 2 is applied phase voltage V. The current I load 2 under the action of the voltage of phase B increases. As in the case of thyristor 14 operation, the relay element opens, and then closes key 8, and closes and closes key 23. The diode distributor 9 of pulses supplies a control signal to thyristor 16, the anode of which now has the highest potential along the circuit: phase C of distributor 9, diode 11, control electrode of thyristor 16, cathode of thyristor 16, closed switch 8, limiting resistor 17, common point of diode distributor 9. Thyristor 16 is opened and phase C is applied to load 2 The notes of the proposed apparatus is repeated. Thus, the device operates in the self-oscillation mode with a frequency of 3f, where f is the frequency of the mains supply. DC amplifier 5, trigger. Schmidt 6 and key 7, being components of the relay element 3, carry out its operation and control the position of contact 8 depending on the above ratios (U-KI) and ± D. With a large input control voltage U, the voltage UQ, KI of the current sensor 1 does not have time to reach U + b during the operation of one thyristor, the relay element does not work and its contact 8 remains closed. The pulse distributor 9 supplies control signals to each of the thyristors .14-16 during the time the thyristor anode is at the highest potential, which ensures the maximum voltage across the load until it reaches the voltage U. KI values

.i + d.

1 Thereafter, a considered higher self-oscillating pj is established.

 With a stepwise decrease in the control voltage U, the voltage U0c, KI of the current sensor 1 becomes greater and + D. The key 23 is closed. And the key 8 is opened. The thyristor having the most positive potential at the anode, the control pulse does not flow to the next on-time order, therefore, the thyristor continues to conduct, at the current moment, the conducting current. Inverter distributor 18 pulses feeds control signals to each of thyristors 14-16 at a control angle oL 180 -3-O. The valve converter goes to the inverter mode with the maximum negative rectified voltage on the load until the current t of load 2 drops to the specified one.

The use of the proposed device for controlling a valve converter provides an extension of the functionality of the valve converter by introducing an inverter pulse distributor into it, in the neutral wire of which an additional key of the relay element is included,

allowing the pa6oTatt converter to be inverted to inductive load with an abrupt decrease in the control voltage; Improving reliability converters

| since the introduction of an inverter pulse distributor into it eliminates the possibility of single-phase rollover, which will increase; quality indicators valve converter.

Claims (1)

Invention Formula Single Channel Device For controlling a valve converter with a cathode group of thyristors auth. St. 862349, characterized in that, in order to extend the functionality by reducing the transient time, it is equipped with an inverter diode distributor, an additional key of a relay element, and a relay element - an inverse output, and an additional key of the relay element is connected to the neutral conductor of the inverter diode I distributor, its control input is connected to the inverse output of the relay element.