SU741471A1 - Device for starting the group of series-connected thyristors - Google Patents

Description

each storage capacitor, resistors, shunt thyristor control transitions and a resistor equalizer voltage on the thyristors, a pulse transformer is inserted into the trigger circuit of each thyristor, one winding of which is connected in series with the additionally inserted diode into the discharge circuit of the corresponding storage capacitor, and the other is connected through a resistor to the thyristor control transition, and the pulse transformers of the starting circuits of all the thyristors of the group have an electric or magnetic w bond.

FIG. 1 is a circuit diagram of a device for starting four series-connected thyristors; in fig. 2 oscillogram of the control current of one of the thyristors. The device contains a group of four serially connected thyristors 1, 2, 3 and 4, in which the cathode of one extreme thyristor 4 is grounded, and the aode of the other extreme thyristor 1 is the anode of the group of thyristors 1, 2,3, 4 and is connected to terminal 5, parallel to each thyristor are resistors b, 7, 8 9, which serve to equalize the static voltage on the thyristor

The thyristor startup circuits contain storage capacitors 10, 11, 12, and 13. Each of the capacitors 11, 12, 13 is connected by one lead to the control electrode of the previous thyristor 1, 2, 3, the terminal of the outer capacitor 10 is connected to the anode of the extreme thyristor.

Pulse transformers 14, 15, 16 and 17 are introduced into the thyristor startup circuits,

The primary windings 18, 19, 20, 21 22, 23 and 24 of each of the transformers 14, 15, 16 and 17 are connected in pairs. They provide electrical connection between transformers and can be eliminated by using one multiwinding transformer. Control pulses from an external generator are applied to the winding 24. The windings 25, 26, 27 and 28 are connected through resistors 29, 30, 31 and 32 to the thyristor control junctions 1, 2, 3, 4. The windings 33, 34, 35 and 36 are connected in series with resistors 37, 38, 39, 40 and 41, 42, 43, 44 in the discharge circuit of capacitors 10, 11, 12, and 13, respectively. Charging diodes 45, 46 47 and 48 are connected in series with capacitors 10, 11, 12 and 13, respectively, in their charge circuits.

Resistors 49, 50, 51, 52 shunt the thyristor control transitions to increase the stability of the device to the effects of increasing voltage and long-term effects of constant voltage. Terminal 53 serves to power the thyristor 4 from the source of negative bias.

When a voltage is applied to terminal 5, the charging current of capacitors 10, 11, 12 and 13 passes through a series circuit: terminal 5, thyristor anode 1, capacitor 10, diode 45, in parallel, connected thyristor control junction 1, resistor 49, secondary winding 25 pulse transformer 14 and a resistor 29, then a capacitor 11, a diode 46, etc. to the ground. Passing through the control yugcia tirisgoro junctions 1, 2, 3 and resistors 49, 50, 51, the charge current of the capacitors creates a negative bias on them. To thyristor 4, a negative bias is supplied from an external source. After terminating the capacitor charging process, the voltage is uniformly divided between the intermittentrs 1, 2, 3, and 4 with the help of a static voltage divider formed by resistors 6, 7, 8, and 9, each of which is connected in parallel to the anode-cathode of the thyristors 1, 2, 3 and four.

When a control signal is applied to the winding 24 of the pulse transformer 17, the control pulses through the windings 18, 19, 20, 21, 22 and 23 are fed to the pulse transformers 14, 15, 16, and from the windings 25, 26, 27 and 28 to the control electrodes thyristors 1, 2, 3 and 4 through the limiting resistors 29, 30, 31 and 32 almost simultaneously. The inclusion of resistors 29, 30, 31 and 32 is practical at the same time. The inclusion of thyristors 1, 2, 3, and 4 after the supply of a control pulse may, due to the technological variation of their switching parameters, occur non-simultaneously. Let one of the thyristors, for example, thyristor 4, be switched on first (has a minimum turn-on delay). After the thyristor 4 goes into the open state, the voltage across it drops and the capacitor 13 begins to discharge in the circuit of the control electrode of the thyristor 3, open thyristor 4, winding 36 of the pulse transformer 17, resistor 40, diode 44, biased in direct direction. By this, additional current is supplied to the control electrode of the thyristor 3 and through the transformer connection through the windings 18, 19, 20, 21, 22 and 23 the additional control current is simultaneously supplied to the control electrodes of the non-connected thyristors 1, 2 and 3 and t, d. Due to the electrical and transformer connection between the windings, devices with a large switching on delay are pulled in, and the energy stored by the capacitors is effectively used.

to enable and maintain the on state of all thyristors regardless of their sequential. unlock

The interconnection of the windings of the impulse transformers 14, 15, 16 and 17 must be designed in such a way that the discharge of capacitors 10, 11, 12 and 13 through the windings 33, 34, 35 and 36 also causes a positive control current of thyristors 1,2, 3 and 4 An example of such an inclusion is shown in FIG. one.

The oscillogram of the control current of all thyristors after turning on one of the devices is shown in FIG. 2. During the time Oh-i acts a short pulse from an external generator of trigger pulses. At time point -fc, one of the thyristors is turned on and for a time1, -2 a control current acts, which is transformed when the capacitor discharges through the open thyristor. The dotted line shows the increment to the control current, obtained as a result of the interconnection of the thyristor starting circuits through pulse transformers.

The number of thyristors in the device can be large and practically unlimited.

Claims (1)

Invention Formula A device for starting a group of series-connected thyristors containing a transformer group start circuit, storage capacitors in the start circuits of each thyristor connected in series from the rear and diodes between the cathode of each thyristor and the control electrode of the next, the current-limiting resistors in the discharge circuit of each storage capacitor , resistors, shunt thyristor control transitions, and a resistor equalizer voltage on thyristors, characterized in that, in order to reduce The switching time of a group of series-connected thyristors and overvoltages on them in the process of switching on, a pulse transformer is introduced into the start-up circuit of the thyristor, one winding of which is connected in series with the additionally inserted diode into the discharge circuit of the corresponding storage capacitor, and the other is connected via a resistor to the control thyristor, the pulse transformers of the starting circuits of all thyristors of the group are electrically or magnetically coupled.  " Z.f