Converter over-current protection and automatic reset circuit

Abstract

The invention provides a converter over-current protection and automatic reset circuit. The circuit includes a three-phase full-bridge rectification module which is connected with a converter sampling output end and is used for performing rectification processing on current sampling signals, a three-phase unbalance detection module which is connected with the converter sampling output end and is used for detecting the three-phase current unbalance degree of the current sampling signals, an over-current and unbalance degree judgment module which is connected with the three-phase full-bridge rectification module and the three-phase unbalance detection module respectively and is used for judging whether over-current or short circuit occurs on a converter, and a fault signal processing module which is connected with the over-current and unbalance degree judgment module and is used for protecting the circuit when the over-current or short circuit occurs on the converter and making the circuit perform reset processing after the fault is eliminated. With the converter over-current protection and automatic reset circuit adopted, output over-current and short-circuit-to earth protection can be greatly optimized, and a 332J sets a proper short-circuit protection current point, so that an IGBT can comprehensively protect the converter under various over-current and short-circuit conditions.

Description

technical field [0001] The invention relates to the field of frequency converters, in particular to a frequency converter overcurrent protection and automatic reset circuit. Background technique [0002] The frequency converter is a commonly used device in the process of click speed regulation. It is used to realize the stepless speed regulation of AC motors and has been widely used in various fields of the national economy. [0003] At present, the short-circuit overcurrent protection of low-power machines in the inverter industry often uses the following two schemes: (1) The current detection circuit is used for current detection and short-circuit protection; the current signal is added after the detection device (Hall, current detection resistor, etc.) The amplifier circuit and filter circuit are then sent to the CPU for processing; (2) A current detection circuit is added on the bus. Of these two detection methods, the latter has obvious effects, but the cost is high, a...

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