SU614513A1 - Arrangement for control of power thyristor circuit - Google Patents

Description

(54) DEVICE FOR MANAGING POWER TYRISTOR CHAINS

The invention relates to electrical engineering and can be applied in pulse-width converters, inverters, high-power pulse generators to turn on (quench) thyristors using not only the discharge current of the precharged capacitor, but H capacitor charge current at zero and primary voltage. and a transformer (or throttle) connection of the operating driver and the switching device ...

Devices are known in which a precharged capacitor (1) is used for the crm1 load. One (first). (NL several cells) in these devices are preparatory, and the amplitude of the voltage on the switching capacitor in the steady state significantly increases the voltage of the power supply, and with an increase in the load current in the switching. the chains increase further; in addition, the active losses in the charged choke significantly increase.

Thyristor shutdown devices are also known, consisting of a direct current source, charge throttle and commutating nondensatbras (2 |. However, after each turn on of the transistor, the current of the pulse transformer passes through the secondary winding of the pulse, the energy stored by the transformer goes over the oscillating the process to the switching capacitor, the amplitude of the voltage on the switching capacitor is swelled to a value greater than that necessary to turn off the working tyrstbre. EMA device from istochnnka power, znachntelno increased. After incorporation of the power supply device is not ready to immediately shutdown na0 fuzki. be required time during which the voltage on the commuting capacitor dostngiet ustanovivscheys value.

Of the known devices of thyristor switches, in which switching pulses are formed by charging and discharging a capacitor, the closest in technical essence to the invention is a single-phase inverter device, which, in particular, has thyristor quenching circuit, each connected sequentially primary

0 the winding of a pulse transformer, a switching capacitor and a tristor {3 |.

In such a device, in cycles of switching-on of the tristors, subsequent after the first, the voltage amplitude at the switching condator increases with each charge cycle.

Almost the amount of double voltage and power supply. With an increase in the amplitude on the switching capacitor, the energy consumption from the power source increases significantly, and this. requires the need to raise thyristors, increase the cross section of transformer cores, increase the weight and weight parameters of all circuit elements.

A transient process in a quench device of that type when the power source is turned on will reach its steady-state value after 8--10 switching cycles, only after that it will be ready to disconnect the thyristors in the load circuit.

The aim of the invention is to reduce energy consumption and reduce preparation time for work.

This goal is achieved by the fact that a device for controlling power thyristor circuits, containing switching thyristors, switching capacitor, storage capacitor connected in parallel with the power source, control charging choke and pulse transformers, introduces additional reverse diodes, and the control choke switching the capacitor and the switching thyristors are connected in a series circuit connected in parallel to the capacitor, the thyristors being connected to each other rugu opposite and parallel to each of them included the chain consisting of a series-connected pulse transformer and inverse diode.

The drawing shows a diagram of a device for controlling power thyristor circuits.

The proposed device consists of a controllable charge droplet 1, connected in series with switching capacitor 2, which is connected to two successively connected branches, each of which consists of thyristor 3 (4), which is pulsed by the primary winding of a pulse transformer 5 (0) and a diode 7 (8), an anode connected to the cathode of the thyristor 3 (4), with one branch connected by the cathode of the thyristor 3 to the plate of the switching capacitor, and the other by the cathode of the thyristor 4 to the negative pole of the cumulative cond The sensor 9 and the minus of the power source 10, the controlled charge choke 1 is connected to the positive pole of the storage capacitor 9 and the positive side of the power source 10, the switching capacitor 2 is connected to the control circuit I.

The device works as follows. In the initial state, the initial value of the equivalent capacitor 2 is zero. When a control signal is applied to the thyristor 4, the latter is turned on and. c.ep l 2--7 5-4-10 is formed.

The voltage on the capacitor 2 and the current in the circuit are determined by the expressions

Y (t) Ui "(I - costotV

i (t)

1-, lo, si not,

c7

Where

.(ABOUT

I max LJ 1 o

L.H-L +

where 1 „« d

peak value of current in circuit I

sh

where Lcv "L -I- L4

From (1) we get U 2Uo with t

i.e. when the current drops to zero, the capacitor 2 is charged to double the voltage of the power source 10 without negligible loss in the oscillating circuit.

By circulating the charge of the capacitor, the thyristor 4 is turned off by the reverse wave of the current, and the voltage on the capacitor 2 remains.

When the thyristor 3 is turned on, the capacitor 2 is discharged along the circuit 2-1-9-8-6-3, and the energy obtained during the charging process in the previous cycle returns to the source 10. After the discharge of the capacitor 2 to the source 10, the thyristor 3 is turned off reverse wave current oscillatory process; Thyristors 3 and 4 are switched on alternately with a time shift exceeding the period of natural oscillations of each circuit.

Induced in the windings of pulse transformers 5 and 6, the EMF alternately turns off the working thyristors.

The secondary windings of the 1X pulse transformers are connected in series between the poles of the power supply source and the thyristor bridge formed by the working thyristors. In the second diagonal of this bridge, the load is switched on, for example, a low-inertia DC motor. At. zar de

5 switching capacitor 2 disconnects one working thyristor of the diagonal of the bridge, and when discharging the switching capacitor and the power source disconnects the second working thyristor (based on the alternating switching law of the thyristors), this causes a certain delay existing in known devices (equal to several switching periods) between the increase in the load current and the corresponding increase in voltage across the switching capacitor.

The control circuit AND after each cycle of discharge of the coaxial Q to the storage capacitor 9 drops the residual voltage, and therefore the oscillations in the symmetric circuits are continuous.

O The device allows the generation of voltage pulses in the secondary windings of pulse transformers 5 and 6, with a frequency equal to the switching power of thyristors 3 and 4.

The control choke 1 allows the ipB3Tb to regulate the charging current of the switching capacitor. Because. when the thyristor 3 is turned on, the total energy obtained during the charging process in the previous cycle returns to the power supply source, an increase in the voltage across the capacitor 2 during switching is excluded

 f

fn of the HPPNGNIUSHRGG of the VGPGNTNGNG Uarnvnl / u, which is required to ensure reliable shutdown of the thyristors in the load circuit, which ultimately eliminates the need to increase the class of thyristors, to increase the cross section of the magnetic cores of pulsed transformers due to saturation and to increase the dimensioning size of the magnetic cores of the pulsed transformers due to saturation and increase in the overall dimension of the magnetic cores of the pulse transformers due to saturation and increase in the dimensioning size of the magnetic cores of the pulsed transformers due to saturation and increase in the dimensioning dimension of the magnetic cores of the pulse transformers due to saturation and increase in the dimensioning dimension of the magnetic cores of the pulse transformers due to saturation and increase in the dimensioning size of the magnetic cores of the pulse transformers due to saturation and increase in the dimensioning size of the magnetic cores of the pulsed transformers due to saturation and increase in the dimensioning size of the magnetic cores of the pulse transformers due to saturation and increase in the dimensioning size of the magnetic cores of pulsed transformers due to saturation and increase in the size of the transformer. . The time available to work when connected to a power source is almost one first period and does not depend on the load resistance. Thus, the proposed device is faster, more economical than the known. Applying formula A device for controlling power thyristor circuits, containing switching thyristors, switching capacitors, storage capacitors connected in parallel with the power source, a control charge choke and pulse transformers; characterized in that, in order to reduce energy consumption and reduce preparation time, it is equipped with additional reverse diodes, and a control choke, a switching capacitor and switching thyristors are connected in series, connected in parallel with a storage capacitor, and the thyristors are connected relative to each other and parallel to each of them is a circuit consisting of a pulse transformer and a reverse diode connected in series with it. Sources of information taken into consideration during the examination: 1. USSR author's certificate No. {77950, cl. H 02 P 3/12, 1964 .. 2. Golts M., et al. Artificial switching devices for thyristors for pulse-width transforms of electric drive systems. Materials for the seminar “Thyristor Systems of Electric Drive and Industrial Automation Constant Part I of the LTPD, L., 1970, p. 47-49. 3. USSR author's certificate JVs 261546, cl. H 02 R 13/16, 1967