Inverter input and output reverse connection detection and protection method and device

Abstract

The invention relates to a frequency converter input / output reverse connection detection protection method and a frequency converter input / output reverse connection detection protection device. The method comprises the following steps of: 1, detecting the output current of a frequency converter by using an output current detection circuit during initial electrification; 2, comparing an output current value detected in the step 1 with a reference current value by using a first comparison module of a central processing unit (CPU); 3, blocking a driving circuit of the frequency converter by using a first control module of the CPU; 4, detecting the direct-current bus voltage of the frequency converter; 5, judging whether the direct-current bus voltage detected in the step 4 is greater than a current limiting switch switch-on threshold value of a charging current limiting circuit or not by using a second comparison module of the CPU; 6, charging a high-voltage electrolytic capacitor, and continuously limiting charging current by using the charging current limiting circuit simultaneously; and 7, outputting a current limiting switch action signal by using a second control module of the CPU. By the method and the device, the technical problem that an inversion unit power device can be damaged by extremely high charging current generated during the input / output reverse connection of the frequency converter is solved.

Description

technical field [0001] The invention relates to the technical field of frequency converters, in particular to a method and device for detecting and protecting input and output reverse connections of frequency converters. Background technique [0002] Inverter is a speed control device for three-phase asynchronous motors. In recent years, with technological requirements and energy-saving purposes, inverters have been widely used in industrial control applications. In the process of application, because the input terminals and output terminals of the three-phase inverter are very similar, it is very easy for the installer and debugger to connect the input three-phase power supply to the output terminal of the inverter. Damage and endanger the life safety of operators. [0003] figure 1 Shown is a known inverter main circuit diagram, in which the rectifier module 10 rectifies the AC input power into a DC power supply, usually the rectifier module 10 is composed of uncontrolla...

AI Technical Summary

Problems solved by technology

The device has the following problems: from figure 2 It can be seen that although the invention has input and output reverse connection detection and has a certain protective effect on power devices, it does not fundamentally solve the problem of a huge charging current impact during reverse connection, and only uses a fuse to play a role in protecting the power device. Fuse protection function. When the fuse is selected too large, the power device will be damaged. When the fuse is selected too small, the fuse itself will be blown due to the impact current, causing new faults of the inverter and reducing the reliability of the inverter.

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