Power-off synchronous operation method and system for frequency converter

Abstract

The invention relates to a power-off synchronous operation method and system for a frequency converter. The method includes the steps of: S1. monitoring bus voltage in real time by a host frequency converter, and entering Step S2 when the bus voltage is smaller than a preset power-off synchronization value V<llimit>; S2. detecting real-time voltage V of a bus, and calculating actual deceleration time T* according to the real-time voltage V and a preset target voltage V<target>; S3. adjusting the operating frequency of the host frequency converter according to current operating frequency and the actual deceleration time T* calculated in S2, so that the bus voltage is stabilized at the preset target voltage V<target>; and S4. when the operating frequency of the host frequency converter is larger than zero, outputting the operating frequency to slave frequency converters which control operating frequency of themselves to be synchronous with the received operating frequency, and skipping to the Step S2. According to the power-off synchronous operation method, after power-off, the bus voltage is automatically increased and is maintained at the target voltage V<target> in real time, thereby guaranteeing normal operation of a motor, systems with various load inertia are automatically adapted to, and synchronization of slaves is guaranteed.

Description

technical field [0001] The invention relates to the field of textile motors, in particular to a power-off synchronous operation method and system for frequency converters. Background technique [0002] Since most of the motor drives in the textile industry have different load inertias, in the event of an unexpected power failure, the parking time for each machine to free run after undervoltage is inconsistent. This out-of-synchronization can cause problems such as breakage or deformation of the yarn or cloth. [0003] In the textile industry, power-off synchronization is the most demanding synchronous operation method. At present, the industry mostly adopts the parking method that allows each machine to run for the same deceleration time after power-off, so as to achieve synchronous stop after power-off. [0004] The method of setting the same deceleration time is too complicated to debug, because the deceleration time parameter is too large or too small to make the machine...

AI Technical Summary

Problems solved by technology

[0004] The method of setting the same deceleration time is too complicated to debug, because the deceleration time parameter is too large or too small to make the machine undervoltage or overvoltage, and it needs continuous debugging to find the appropriate value

In addition, for the system with changing load, the theoretical deceleration time parameter is not a fixed value, and the applicability of using a fixed value is poor.

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