SU570955A1 - Device for control of capacitor charging - Google Patents

Description

one

The invention relates to contactless switches and can be used in devices for limiting the voltage of a charge of capacitors and devices for stabilizing the voltage of a charge of capacitors when the supply voltage varies over a wide range.

A device for switching off the alternating current is known, in which, when the voltage on a load reaches a certain value or when a short circuit occurs in the load, the controlled valve (thyristor) is locked by connecting an auxiliary, precharged capacitor, which creates a current opposite to the main capacitor in the thyristor.

The disadvantage of this device is that it has large energy losses during the artificial locking of charge thyristors.

The closest technical solution to the invention is the device containing the main thyristors, the switched on switching thyristors, the switching capacitor and the ballast resistor. This device allows the load voltage to be controlled by locking the main thyristors with the help of counter-switched commutating thyristors and a commutating capacitor. However, such a device

It does not allow the charging of two capacitors by voltages shifted in time by 180 e. hail, relative to each other, and has instability in the work.

The purpose of the invention is to eliminate these disadvantages.

The goal is achieved by the fact that the device is additionally equipped with two oppositely connected diodes, the anodes of which are connected to the output to connect the common connection point of the charging capacitors, and the cathodes to the anodes of the main thyristors, the switching capacitor bounded by the resistor connected in parallel to the secondary winding of the transformer through the opposite connected commuting thyristors.

FIG. 1 shows the electrical circuit of the proposed device; in fig. 2 - curves explaining his work.

The device contains a power transformer 1, a ballast resistor 2, two switching thyristors 3, 4, switching capacitor 5, shunt resistor 6, diodes 7 and 8, main thyristors 9 and 10, and charged load capacitors 11 and 12 of channel A and channel B, respectively.

Curve C (Fig. 2) represents the voltage on the secondary winding of the transformer, 0 curves D and E are the voltage at the output of the device in channel A and channel B, respectively, curve F is the voltage on the switching capacitor.

The device works as follows.

When the polarity of the voltage on the secondary winding of the transformer indicated in FIG. 1 in brackets at time ti (Fig. 2) a control pulse passes to the thyristor 9. The thyristor is unlocked and the entire voltage of the secondary winding of the transformer through the thyristor

9 and diode 8 is applied to the charged capacitors of the load 11 of channel A, and the voltage on the latter begins to increase (Fig. 2, curve D). When the voltage on the capacitor reaches a predetermined magnitude, a pulse is applied to the control transition of the switching thyristor 3 (Fig. 2, point 4), the latter opens, and the switching capacitor 5 is suddenly charged from the secondary winding of the transformer (Fig. 2, Curve F). At the moment when the capacitor is charged in the voltage of the secondary winding of transformer 1, a sharp voltage dip appears (curve C, Fig. 2). During this voltage dip, the thyristor 9 is de-energized and locked, and the charge on the load capacitors 11 ends there. The switching capacitor 5 is charged by the inductance of the secondary winding of the transformer to a voltage greater than the voltage of the secondary winding of transformer 1 and locks the switching thyristor 3. When changing the polarity of the voltage on the secondary winding of the transformer to the opposite at the time rz (FIG. 2) a control pulse is applied to the thyristor 10, it is unlocked and the entire voltage of the secondary winding is applied through the thyristor

10 and diode 7 to the charged capacitors of load 12 of channel B. The latter are charged (curve E, Fig. 2) and when the voltage on them reaches a predetermined value (point 4, Fig. 2), a control pulse arrives at thyristor 4, it opens and the capacitor 5, charged by the previous commutation, is recharged, creating a cut-off voltage dip in the secondary winding of the transformer 1, during which the thyristor 10 de-energizes and locks and the load capacitors of the channel B are stopped at this (curve E, FIG. 2). The capacitor 5, charged by the inductance of the secondary winding of the transformer, to a voltage greater than the voltage of the secondary winding, locks the switching thyristor 4. In the future, the circuit starts working with recharging the switching capacitor 5. A large resistor 6, somewhat limiting the voltage on the capacitor 5, stabilizes the operation of the circuit. Resistor 2 serves to limit the current pulses that occur when recharging capacitor 5.

Installation of the proposed device instead of previously used in the previous gives an increase

The coefficient of stabilization of the voltage of the charge capacitors of the load, eliminates the charge of the capacitors at idle of the system power amplifier and increases the reliability of the entire system.

five

Claims (1)

Invention Formula A device for controlling the charge of capacitors, containing a transformer, main thyristors, counter-connected switching thyristors, a ballast resistor and a switching capacitor, characterized in that, in order to reduce switching losses and to provide a charge on the capacitor, the voltages are shifted along 5 times 180 e. hail., it is additionally equipped with two oppositely connected diodes, the anodes of which are connected to the output for connecting the common connection point of the charging capacitors, and the cathodes to the anodes of the main thyristors, the switching capacitor, shunted by a resistor, connected in parallel to the secondary winding of the transformer through the oppositely connected switching thyristors.  ./ l 14/ -L f