SU363171A1 - DEVICE FOR iEMKOCTHOrO TIRISTOR DISABLE - Google Patents

Description

one

There are known devices for capacitive switching off of the thyristor, a diode, a switching capacitor, an omnipotent thyristor, a charging and discharge chokes.

However, the voltage on a capacitor, when turned on, a CEI with an uncharged capacitor, in principle, cannot exceed twice the voltage of the power source. Therefore, at low supply voltages and large switching powers, the capacity of the co-detector unit is relatively large, which leads to an increase in the size and weight of the device.

The aim of the invention is to improve the overall and weight indicators of the device by reducing the size and weight of the switching capacitor.

This is achieved due to the fact that a transformer is used as a charge droplet, the high voltage winding of which is included in the charging circuit of the switching capacitor, and the low voltage winding through a key element controlled as a switching current of the switching capacitor is connected to the terminals power source.

The principle scheme of the proposed device is shown in the drawing.

A working thyristor TI and a bit LT, a rosel L of a switching device are included in the Zn load circuit. The load circuit is connected to a DC power source. In the circuit of the diode Mi and the switching capacitor C, a high-voltage winding HV of the transformer is connected. The low voltage winding of the HH transformer through the key K is connected to the terminals of the source of the thread. Regarding the power source, the transformer windings are turned on bifil.

The key K is controlled by the capacitor charge current function (s. Capacitor C is connected to the cathode of the thyristor TI through the auxiliary thyristor. The load (in the case of an indicative nature) is shunted by the reverse diode D2, and the low voltage winding of the transformer is diode Dz. Consideration of the device operation principle from the moment the power source is turned on with an uncharged switching capacitor. When the power source is turned on, a charging current / s semiconductor or electric current appears in the capacitor charge circuit (HV-C-PI). key K mechanically controlled by a current function v,

is turned on, and the low voltage winding of the transformer is applied to the voltage of the power source, which is transformed during the transient process into the high voltage winding of the high voltage transformer. Since the transformer winding

included bifil rpo relative to the power source, then induced in the high-voltage winding e. d. the induction acts according to the voltage of the power source in the charge circuit of the capacitor. Therefore kon; The sensor is charged before the voltage, 1 above the doubled voltage of the power source. By changing the transformer ratio, you can set the required amount of overvoltage on the capacitor. The charge time of a capacitor is equal to the half-period of natural oscillations and depends on the parameters of the transformer (inductance dissipation of the windings, mutual inductance and transformation ratio) and the capacitor capacitance value. At the end of the capacitor charge process, the diode prevents the change in the direction of current flow in the capacitor.

At (z-O switch / С controlled in current r ;, opens. Diode Dz creates a circuit for the discharge of energy stored in the low voltage winding of the transformer to the end of the capacitor charge process.

When the auxiliary thyristor Go is turned on, the working thyristor Ti is applied a reverse voltage, the voltage difference between the capacitor and the power source, and the Ti thyristor is turned off. The time to maintain the reverse voltage is determined by the duration of the capacitor discharge process along the C-TZ-C circuit to the voltage of the power source.

By creating the required degree of overvoltage on a capacitor, it is possible to switch large powers with a relatively small capacitance value, i.e., to improve the device’s weight and dimensions.

Subject invention

A device for capacitive switching off a thyristor containing a diode, a switching capacitor, an auxiliary thyristor, charge and discharge chokes, characterized in that, in order to improve its overall and weight indicators, a transformer is used as a charge choke, the high voltage winding of which is included into the charging circuit of the switching capacitor, and the low voltage winding through a key element controlled as a charging current of the switching capacitor is connected to the power supply terminals.