Current-sharing bypass circuit of power unit of high-voltage inverter

Abstract

The invention provides a current-sharing bypass circuit of a power unit of a high-voltage inverter. The current-sharing bypass circuit comprises a single-phase full-wave diode-bridge rectifier arranged beside an H-bridge inverter, a first thyristor, a second precharging resistor, a first buffer circuit, a second thyristor, a second precharging resistor and a second buffer circuit. The cathodes of two diodes, connected with the direct-current positive output end of a bridge rectifier, in the single-phase full-wave diode-bridge rectifier are connected with the anode of the first thyristor and the anode of the second thyristor respectively, and the anodes of two diodes, connected with the direct-current negative output end of the bridge rectifier, in the single-phase full-wave diode-bridge rectifier are connected with the cathode of the first thyristor and the cathode of the second thyristor respectively. The current-sharing bypass circuit can effectively solve the problem of serious heating of a single thyristor.

Description

technical field [0001] The invention relates to a bypass circuit, in particular to a bypass circuit of a current-equalizing high-voltage frequency converter power unit. Background technique [0002] With the development of power electronics technology, the application of high-voltage frequency converters is becoming more and more extensive. The high-voltage frequency conversion device composed of power units in series is favored by the majority of users for its excellent performance such as small harmonics and convenient maintenance; the power units are connected in series. During the operation of the high-voltage frequency conversion device, the whole device may fail to operate normally due to the failure of individual power units. In order to improve the stability and reliability of the device, it is necessary to temporarily bypass the faulty power unit to ensure that the device can Continue to run normally. [0003] A form of bypass circuit that is commonly used now is a...

AI Technical Summary

Problems solved by technology

[0004] Under this circuit topology, since only one thyristor participates in bypass operation, limited by the current manufacturing level of power semiconductor devices, the conduction capacity of a single thyristor is limited. When the current conduction capacity of a single thyristor is lower than the actual demand

In order to meet the bypass requirements of the power unit of the high-voltage frequency converter with large power, one method is to use thyristors with larger capacity and stronger conductivity. progress; another approach is to modify existing circuit topologies to meet the above requirements

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