SU1367117A1 - Thyristor inverter - Google Patents

Abstract

The invention relates to a converter technique. The aim of the invention is to increase the reliability of the inverter by protecting the thyristors against overload in case of inversion failure. The device contains two thyristors 4, 5 connected in series with each other, and the actuator of the sensor 10 and the trip circuit of relay 1. In succession, two diodes 6.7 are connected to the thyristors, the common point of which forms zero zero and is connected to the output inverter. The operation of the relay with inversion may occur at a through-current less than the load current. 1 il. i (L

Description

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The invention relates to electrical engineering, in particular, to converting technology, converting a constant voltage to an alternating voltage.

The aim of the invention is to increase the reliability of the inverter by protecting the thyristors against overload in case of inversion failure.

The drawing shows a circuit of a thyristor inverter.

The protection actuator in the form of the opening contact of the relay 1 is connected to the power supply 2 via a current-limiting filter 3. Consistently with the valves (thyristors) 4 and 5, diodes 6 and 7 are connected, the common point of which forms the zero output and is connected via a capacitor 8 and load 9 with the midpoint of the filter 3, and the current protection sensor 10 in the form of a relay coil is connected between the common junction point of the anode of one diode 6 and thyristor 4 and the common junction point of the cathode of another diode 7 and another thyristor 5.

The inverter works as follows.

When the thyristor 4 is turned on (in particular, when a trigger pulse is applied to the thyristor), the current passes over the arm: thyristor 4, diode 6, capacitor 8 and load resistance 9. The current flows until those liop until a positive potential is formed on the capacitor plate 8, or a little more than half of the supply voltage, the current will no longer flow along this shoulder. Then the thyristor 5 is turned on and the current passes through the circuit: load 9 — condensate ator 8 — diode 7 — thyristor 5, similarly, the flow of current occurs for a period equal to the recharge time of capacitor 8.

When the inverter is in operation, thyristors 4 and 5 and diodes 6 and 7 alternately open, and there is no voltage on the winding 10 of the relay.

At the time of stalling, the inverts are simultaneously open.

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thyristors 4 and 5, a through current flows through both arms. A through current also flows through the relay coil of the sensor 10, which has a lower resistance than the resistance of the diodes 6 and 7 in the forward direction. Relay 1 trips, its contacts open. The current flowing through the thyristors 4 and 5 drops, the thyristors 4 and 5 turn off and restore their control properties, the contact of relay 1 closes, and again the anode voltage on the thyristors appears.

The relay can be triggered when the inversion fails. It can occur at a through-current less than the load current. From here, even if the inversion fails, the overloading of the thyristors does not occur. This increases the reliability of their work and, consequently, the reliability of the inverter.

The automatic inclusion of the inverter in operation after the restoration of the control properties of the thyristors ensures the continuity of the operation of the power supply device.

Formula inventions

A thyristor inverter containing a half-bridge connected to the input terminals through the protection executive and a current-limiting filter, in each arm of which two valves are connected in series, the common point of the half-bridge arms being connected via a load circuit and a switching capacitor to the midpoint of the said filter, as well as a current protection sensor That is, in order to ensure the reliability of the inverter by protecting the thyristors from overload in case of inversion failure, as gates, which form w shoulder point half bridge diodes are used which zashunti- the sensor is overcurrent.

Claims (1)

Claim A thyristor inverter containing a protective actuator connected to the input terminals through 25 and a half-bridge current-limiting filter, in which a larger voltage than half of the house’s power supply arm incorporates back-voltage, the current will no longer flow along this arm. Then the thyristor 5 is turned on and the current passes through the circuit: load 9 - capacitor 8 - diode 7 thyristor 5, similarly, the current flows over a period equal to the time of recharging the capacitor 8. When the inverter is operating, thyristors 4 and 5 and diodes 6 and 7 alternately open, and there is no voltage on the relay winding 10. During the inversion failure, two gates are opened at the same time, moreover, the common point of the half-bridge arms is connected via a 4θ load circuit and a switching capacitor to the midpoint of the filter, as well as a current protection sensor, characterized in that, in order to increase reliability 45 operation of the inverter by protecting thyristors against overload when the inversion is interrupted, diodes that are shunted by a current protection sensor are used as valves forming the common point of the half-bridge arms.