| The gantry crane is the main equipment in the port operation, the quality of whichhas an important influence on the productivity of the port. With the development ofscience and technology, power components, amplifying elements constantly updated,,AC speed regulation system with its superior performance gradually replace other ACmotor speed control modes, and even the DC motor speed control system.This paper is derived from the40t crane upgrading project of the Tianjin fifthport company limited. Based on the PLC and inverter technology, this paper includesthe upgrading of hoisting mechanism, traveling mechanism, luffing mechanism androtating mechanism. Firstly, this paper introduces the background of this project,analyzes the domestic and foreign research on frequency control and sets the goals ofthe upgrading based on the actual situation of the project. Secondly, in order to furtherimprove the mechanism’s accuracy and overload capacity, this paper adopts thefrequency vector control technology and has a deep research on the principle of it,realizing the control of the AC motor just like the DC motor. Taking the rotatingmechanism as an example, this paper gives a deep description of the choice of variouscomponents, the design of the schematic and the software of the control system. Thecrane’s monitoring system adopts the technology of PROFIBUS-DP bus, combiningthe basic control of performers and on-site state alarm monitoring and theoptimization and management functions together, which makes on-site monitoringmore convenient and its stability has also been improved.After experimental testing, the upgrading makes the crane system more stable,fully functional and more accurate. Each institution has higher control precision, toovercome the original V/F in the speed control system of motor control accuracy isinadequate, insufficient overload limited capacity;This project has effective utilizationof the original old equipments, motors, brakes and other equipments, saving the costof renovation. |
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