Closed Loop Control System For Frequency Control Mine Hoist Applications

Research content of this thesis is about a new mine lifting machine transport system, which is based on frequency converter and uses PLC as its control module. This thesis introduces the current situation of development of the lifting machine transportation system of the mine, and the importance and necessity of research this system. In our research, we proposed the performance indexes of control system, control principle and control request, proposed the control strategy and method of this control system. The research contents mainly include:(1) Under the control of PLC, and adopting high-power frequency conversion vector control and the computer real-time online control technology. The difficult problem of lifting machine, such as heavy load, stepless speed regulation on long distance, had been resolved. The application of advanced technology has raised systematic transport capacity, reliability, and continuity greatly.(2) The variable-frequency speed regulating system of mine lifting machine is a closed-loop control system. This thesis explains the construction of closed-loop variable-frequency speed regulating system, type selection of the frequency converter, the design of digital PID controller and it's role in steady speed, the realization of PLC combines with the frequency converter. Utilize PID control method to increase the system performance.(3) The system adds one position and pace monitor and protection system in lifting machine, This protection system has pronunciation and picture alarm, can point out trouble point at once as the system breaks down, helping fix a breakdown on shortest time, reduce losses, increase the benefit. Realize control to mine journey and pace of lifting machine in real time. The state,velocity and velocity graph of the lifting machine can be shown in the touch-sensitive screen dynamically.The mine lifting machine variable-frequency speed regulating control system based on PLC has undergone industry test, each link of control system turn round basically normal. The application of advanced technology has raised systematic transport capacity greatly, increased feasibility and continuity that the system operates. Economic benefits and social benefit are prominent, it has broad popularization prospect.