SU499639A1 - Stand alone serial inverter - Google Patents

Description

(54) AUTONOMOUS SERIAL INVERTER

one

In the known circuits of autonomous series inverters with counter-connected reverse thyristors with a wide range of load variation, voltage increases on the circuit elements are possible.

In order to increase the stability of WHeepTHs in the proposed inverter, the secondary windings of current transformers in each arm of the bridge are connected to the control by means of electrodes of check valves of the Antiphase bridge.

The drawing shows the scheme of the proposed inverter, contains it. valve bridges 1 and 2, formed by main 3-10 and reverse 11-18 controllable valves, switching capacitors 19, 20 and throttles 21, 22. Bridges are connected to a load 23 compensated bypass, with a capacity of 24. The intermediate point of load is connected with a negative power supply terminal through a filter choke 25, and with a positive power supply terminal through a filter capacitor 26 and a choke 27. In series with valves 3-10, the primary windings of current transformers 28-35 are connected, the secondary windings of which are connected to control of the corresponding counter-controlled anti-phase bridge valves.

The inverter works as follows.

Claims (1)

In the nominal mode, the external control system simultaneously switches on the direct 3, 4 and oncoming 17, 18 valves. At the same time, the recharge current of the switching capacitor 19 flows through the left half of the load from left to right, and the partial discharge current of the switching capacitor 20 flows through the right half of the load in the same direction, i.e., from left to right. The current through the valves 3, 4 and 17, 18 includes - direct 7, 8 and counter-I, 12 valves. At the same time, the recharge current of the capacitor 20 flows through the right half of the load from right to left, and the partial discharge current of the capacitor 19 flows through the left half of the load in the same direction, i.e., right side of the load. It is the opposite with respect to the first half period. Further switching processes are similar to those considered. With some delay after the current ceases, the valves 7, 8 and 11, 12 turn on the straight 5, 6 and opposite 15, 16 gates and the current in the load again flows from left to right, then the direct 9, 10 and opposite 13, 14 the valves, the current through the load flows from right to left, and so on. Simultaneously with the control impulse, a control impulse generated by an appropriate current transformer, for example, a control impulse comes from the external control circuit 18 transformer ra current 28 in series with valve 3. In nominal operation with this pulse current transformer e has a special meaning, ie. k. a counter-valve still has switched from the external control system. However, a control pulse from a current transformer is necessary in under load compensation mode. It is known that when the load is undercompensated, the intrinsic frequency of the switching circuit decreases sharply, and the operating time of the valves increases. At the same time, the control pulses for the oncoming valves are formed earlier than the direct voltage is established on these counter valves, due to which they do not turn on. This leads to a sharp increase in voltages on all elements of the investor, if there are no additional control pulses. In the proposed design, these additional pulses are formed by means of current transformers connected in series with the corresponding linear antiphase bridge valves. Claims of the invention A stand-alone serial inverter comprising two single-phase thyristor bridges with commuting LC circuits in alternating current diagonals and primary windings AND current transformers on each bridge bridge, shunted by a counter-parallel check valve, characterized in that, in order to increase the inversion stability, secondary the windings of current transformers are connected to control electrodes of the antiphase bridge check valves.