Application Research On Speed Control System Of Double-fed Coal Mine Hoist

In the recent years，more and more attention has been paid on the energy conservationin industrial processes with the development of science and decline of environment. It is ofvital importance for the entire industrial as the coal mine improve its hoist system to reducethe energy consumption.The development and technology status of converter used to control mine hoist wasdescribed in this paper firstly，and advantages and disadvantages of different multi-levelconverters was introduced to make the decision that why the three-level back-to-backconverter was chosen in this paper. In the second chapter, the hoist equipment was taken in toexplain its operation and principle, and the KYN28A-12type high-voltage cabinet wasbrought in during the mine hoist power supply system design. Then, according to thecharacters of double-fed converter system, the10kV power supply and distribution wasdesigned.In the fourth chapter, the speed control system of asynchronous motors was introduced,where the feature and principle of double-fed speed control system were stated as importantparts. What‘s more, five working status of power balance and speed control process wasanalyzed and the main circuit calculation based on this status was completed. In this maincircuit calculation the converter, rectifier transformer, DC-capacitor, reactor, IGBT choosingand calculation were accomplished. The simulation of three-level inverter using MATLABwas conducted, and the simulation results shown that the out-put line voltage is three-leveland its other performances are consistent with the principle analyzed above, which proves thecorrectness of schemes.In the fifth chapter, the PLC control and protection system was designed, includingS7-300PLC hardware configuration, and the signal system and equipment was analyzed aswell. In this system, the digital tachometer program was programmed, which was proven tobe effective in practice. Finally, the whole system working in coal mine for a long time, andits performance shows that the new system comparing with the old one has a much fluentspeed control process, much larger starting torque, much smaller vibration, much highersafety and effectiveness. In a word, all of this proves the success of this design.