Research And Design Of Permanent Magnet Variable Frequency Automatic Tensioning Device Of Belt Conveyor

One of the main functions of the belt conveyor tensioner is to provide enough tension for the conveyor belt to prevent the slipping of the conveyer belt,and to meet the draping requirements of the belt conveyor for reliable operation.The wide use of large belt conveyor makes the belt tension becomes more complex and the deformation increasing,which requires the tensioning device to be able to respond quickly and increase the tension stroke.Therefore,a new type of tensioning device is urgently needed to meet the operation requirements of large belt conveyor.In view of the defects of slow responding speed and short tensioning stroke,a new type of permanent magnet variable frequency automatic tensioning device is proposed in this paper.This device uses permanent magnetic frequency conversion system to drive the tensioner belt directly,reducing the gear reducer,tensioning oil cylinder and large hydraulic station.It can not only simplify the installation,but also respond quickly to tighten the conveyor belt,which shortens the response time,greatly improves the tension efficiency,and increases the tensioning stroke of the tensioning device.In this paper,the dynamics principle of the belt conveyor is studied and analyzed.The structure of the permanent magnet frequency conversion automatic tensioning device is established by using the mechanical,electrical and hydraulic theories.This paper designs the electrical control system of the device,determines the PLC module,the frequency converter,and formulates the control strategy of the tension monitoring device and the braking system.The principle of permanent magnet synchronous motor and the mathematical model in different coordinates are studied and analyzed.The different control techniques of permanent magnet motor are compared and analyzed.Considering the comprehensive consideration,used vector control technology to adjust the synchronous motor's speed.Based on MATLAB/Simulink software,established simulation model of permanent magnet speed control system,verified the feasibility of the permanent magnet speed control system.Established the mathematical model of each component of the permanent magnet variable frequency automatic tensioning device,analysed the influence of the model parameters on the tensioning speed,proposed the strategy of shortening the response time of the tensioning process.Based on the co-simulation of AMESim and MATLAB/Simulink software,established the model of belt conveyor and permanent magnet frequency automatic tensioning device,obtained the dynamic characteristic curves of the belt conveyor under the starting and normal operating conditions.verified the permanent magnet frequency conversion automatic tensioning device designed by this paper makes belt conveyor has faster responding speed and better robustness comparing with the existing automatic tensioning device.