Pre-charging and fault protection integrated device of frequency converter

Abstract

The invention provides a pre-charging and fault protection integrated device of a frequency converter, and relates to the technical field of frequency converters. A pre-charging circuit and a fault protection circuit are integrated to realize pre-charging and fault protection functions of the frequency converter. After that a system has a fault, a contactor of a main loop is disconnected; and after that the fault is removed, the system is re-electrified, the pre-charging function is recovered rapidly, and a normal work state is recovered. The pre-charging circuit and the fault protection circuit of the frequency converter are considered in a unified manner, a protective measure is added to a protection method of carrying out fault blocking and wave generation on the switch tube of the inverter, and the device is safer and more reliable; the pre-charging and fault protection circuits are separated from the control unit, and electromagnetic interference of strong power signals on weak control signals is reduced; and a charging resistor is controlled by both a power electric switch and a charging threshold signal, a supporting capacitor is prevented from repeated charging and discharging, and the service life of the charging resistor is ensured.

Description

Technical field [0001] The invention relates to the technical field of frequency converters, in particular to an integrated control circuit. Background technique [0002] The pre-charging circuit is an indispensable part of the voltage-type AC-DC-AC inverter. When the system is powered on, the supporting energy storage capacitor of the intermediate DC link is first pre-charged and protected, and the bus voltage is established to avoid a huge impact at the moment of power-on Current, to achieve the protection of the inverter power module. [0003] The traditional pre-charging circuit is generally formed by connecting a charging resistor R across the two ends of the main circuit contactor, and real-time detection of the voltage signal across the supporting capacitor C realizes the access and removal control of the charging resistor R, and its structure is simple. However, this type of circuit cannot disconnect the contactor in time when the system fails, and cannot protect the subse...

AI Technical Summary

Problems solved by technology

In addition, since the charging resistor is directly connected to both ends of the contactor, as long as the voltage at both ends of the supporting capacitor is lower than the preset pre-charging threshold voltage, it will be in a charging state and will not be controlled; for some applications with frequent starts, due to frequent starts, The process of repeated charging and discharging will occur, which will affect the life of the charging resistor R

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