SU493879A1 - Voltage inverter - Google Patents

Description

one

Voltage inverters are known, containing in each phase two power thyristors shunted by reverse diodes, two commuting thyristors and a commuting LC-chain connected between the common points of the serial connection of the main and commutating thyristors.

The purpose of the invention is to increase the efficiency. inverter.

This is achieved by the fact that, in the proposed inverter, reverse counter-parallel restrictive thyristors are connected to the serial point of the commuting condisator and the throttle.

FIG. 1 is a schematic diagram of the proposed voltage inverter; in fig. 2 shows time diagrams of a voltage across a switching capacitor and a current in a switching circuit.

Each phase of the inverter consists of two shoulders containing power thyristors 1 and 2, tripped by reverse diodes 3 and 4, switching thyristors 5 and 6, and a common serial switching circuit consisting of a capacitor 7 and throttle 8. To the junction point of the capacitor 7 and throttle 8 connected restrictive thyristors 9 and 10.

The voltage inverter operates as follows.

Let the thyristor 1 be turned on in the phase L to time point (fig. 2). The capacitor 7 is charged before the voltage of the power source. At the moment of time / o, a control pulse is applied to the thyristor 5. After turning on the thyristor 5 in the circuit from the elements 7-5-1-8, a current begins to flow towards the load current. At time ti, the loop current / k becomes equal to the load current, the thyristor 1 is turned off, the total load current and the oscillating circuit begins to flow through diode 3.

At the moment in time fe, the current / k becomes again

equal to the load current, diode 3 is turned off. If the time of current flow through diode 3 is enough to restore the control capacity of the thyristor 1, then this thyristor is turned off. Starting from the moment

time tz, a circuit is formed (7p 5-7-8-1. Load current / n, flowed through this circuit, recharges the capacitor 7 to the voltage of the power source. At time / 3, when the voltage on the switching capacitor 7 becomes

power supply voltage included

restrictive thyristor 9, and reload

switching capacitor is terminated.

At the same time, when the thyristor is turned on

2 main bridges did not get short ..; .. ",

The closed loop 2-8-9, it is necessary to combine the moment of switching on the thyristor 2 with the moment of passage of the phase current through zero (moment 4).

Subject invention

A voltage inverter, containing in each phase two power thyristors shunted by reverse diodes, two commute493879

thyristor and commuting LC-chain, connected between common points of the serial connection of the main and commuting thyristors, characterized in that, in order to increase the efficiency inverter, to the point of the series connection of the switching capacitor and the throttle are connected opposite counter-parallel thyristors.

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