SU478399A1 - Compensation converter - Google Patents

Description

(54) COMPENSATION CONVERTER5

one

 In the well-known compensation circuits, 1 non-transducers are non-renanzers on the elements of the artificial switching node and in the network.

The aim of the invention is to reduce the non-stress on the circuit elements.

This is achieved by the fact that, in series with the switching circuit of the LC circuit, there is a coenoltage of a series-connected diode and throttle shunting. a counter-connected thyristor, the control electrode of which is connected to the cathode of the diode.

The principal scheme of the proposed compensation converter is shown in the drawing.

It consists of a main converter 1 operating at load 2, a non equal equal rectifier 3 with a filter 4 capacity at the DC terminals, switching thyristors 5 and b, shunted by counter-on diodes 7 and 8, switching capacity 9, comm. inductance 10, charge diode 11, charge droplets 12, auxiliary thyristor 13, and diodes 14 and 15 connecting the switching node with the load 2.

In order to artificially turn off the conductive veytil in any group of power converter 1, commutation thyristors 5 and 6 are switched on, and switching capacitor 9 begins to resonantly recharge via chokes 10 and 12, diode 11, filter capacitor 4 and thyristors 5 and 6. At the same time the connected thyristors 5 and b and the diodes 14 and 15 of the filter capacitor 4 are connected in parallel with the load 2, and since the voltage on the capacitor 4 is greater than the output voltage of the converter 1, the latter turns off and the load current 2 begins to flow through filter capacitor 4. Through the half-period of natural oscillations of the circuit formed by chokes 10 and 12 and capacitors 4 and 9, the current through the switching capacitor 9 changes sign, which leads to turning off the thyristors 5 and b and turning on the thyristor 13 and diodes 7 and 8, t. that is, the switching capacitor 9 is reversed through the switching choke 10. When the switching capacitor 9 is reversed, when the current decreases to the load current, the diodes 7 and 8 turn off, and the load current starts to flow through the switching capacitor 9, the choke 10, the thyristor 13 and the diodes 14 and 15. At this point, a control pulse must be applied to turn on the next valves of the converter 1. The switching of the current from the switching capacitor circuit to the power converter circuit will begin from time when the voltage across the capacitor becomes equal to commute linear voltage transducer same NIJ 1. Due to the presence of the inductance on the side AC converter switching process 1 is tightened, so the commutating capacitor continues recharged part of the load current. When the voltage on the capacitor is comparable to the voltage on the filter capacitance, part of the load current flowing through the switching capacitor will go to the filter capacitance circuit, flow through the open valves of the converter 1 and the corresponding uncontrolled rectifier valves 3. into the AC mains occurs under the action of a linear voltage difference between the turned-on valves of the power converter 1 and the voltage across the capacitor of the filter 4. At this last stage of switching, the condensate The filter driver receives an excess charge, which is transferred to the load in the first stage of the next switching. 994 {The maximum difference between the linear amplitude of the supply voltage and the voltage across the capacitor. / Filter, all other conditions being equal, determines the time during which the capacitor can discharge to the load, and with increasing discharge time the maximum the voltage across the filter capacitor decreases. In the proposed converter, the discharge time can be easily increased due to others 12, without changing the power of the rest of the switching elements. Thus, it is possible to reduce switching overvoltages in the converter without increasing the capacity of the switching capacitors and the inductance of the switching throttle. Subject of the invention: Compensation converter containing controlled and uncontrolled bridge rectifiers, a filter capacitor1 connected to unmanaged rectifier DC terminals, switching LC circuit connected through thyristors, coupled with oppositely connected diodes to a filter capacitor, different by the fact that, in order to reduce the overvoltages on the circuit elements, a chain of series-connected diodes and Drossel are connected in series with the C – C circuit, they are interlocked a thyristor whose control electrode is connected to the cathode of this diode.