Crane brake control method and system

Abstract

A brake control method for a crane, the method comprising: when a variable-frequency drive (200) configured to control a crane and being in an off state receives an operation instruction, starting up according to the operation instruction; increasing an output frequency of the variable-frequency drive (200) to a brake release delay frequency, the brake release delay frequency being greater than a brake release frequency required for releasing a brake (500); and upon an output current and output torque of the variable-frequency drive (200) reaching a required condition for a current load of the crane, the variable-frequency drive (200) sending to the brake (500) a brake release instruction. By changing the output frequency of the variable-frequency drive according to different current states of the variable-frequency drive and received instructions, controlling the brake to be released or switched on, continuously acquiring the output current and output torque of the variable-frequency drive, and acquiring a state feedback of the brake in real-time, the present invention ensures the variable-frequency drive to have a sufficient output torque for each lifting or lowering process of the crane, and enables the brake to release or brake sufficiently, thus preventing a hook failure.

Description

【Technical field】 [0001] The invention relates to the field of frequency converter control, in particular to a braking control method and system for a crane. 【Background technique】 [0002] In the traditional crane industry, the crane is generally controlled directly by the power frequency through the electrical control system. With the continuous development of power electronics technology and frequency conversion technology, and the requirements of complex operations of modern cranes, the frequency conversion control of cranes has been more and more widely used. [0003] However, because many frequency converter manufacturers do not have a deep understanding of the technology and principle of the crane, they have not achieved a good cooperation between the frequency converter and the electrical control part of the crane, resulting in the potential safety hazard of the hook slipping during the start-stop process of the crane, especially when it is fully loaded. And the sec...

AI Technical Summary

Problems solved by technology

[0003] However, because many frequency converter manufacturers do not have a deep understanding of the technology and principle of the crane, they have not achieved a good cooperation between the frequency converter and the electrical control part of the crane, resulting in the potential safety hazard of the hook slipping during the start-stop process of the crane, especially when it is fully loaded. And the secondary lifting of heavy objects hovering in the air is more prone to slip hooks

[0004] The reason is that the traditional braking control of the crane does not fully combine the operating state of the crane to control the state of the frequency converter, and does not fully consider the influence of the closed state of the brake on the hook sliding phenomenon. Complete fault protection measures, and these are often important factors that cause the phenomenon of hook slipping during the working process of the crane

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