The Research On Direct Torque Control Applied To Shearer Frequency Speed Regulation System

Shearer is one of the important equipment for achieving coal mine production mechanization and modernization. The development of shearer traction technology from the chain traction to no chain traction. The Electric Traction Shearer has more advantages, therefore, the world's major mining countries have developed various forms of electric traction Shearer. Mining Electrical and Mechanical traction in two ways: DC traction and AC traction. DC traction is a DC motor speed control system, AC traction is a squirrel cage induction motor AC-DC-AC Frequency Control System. DC traction control has the advantage of being simple, good speed performance, but DC motor bulky, complex structures, and poor reliability, and repair difficulties. AC traction is adopted squirrel-cage motors, small size; explosion-proof structure is simple, reliable, long life and easy maintenance. In the same size factor, the power of AC motor is greater which can do more conducive to the high-power electric traction Shearer, high reliability direction. Its technical difficulty, mainly in the variable frequency AC motor drive speed systems. Direct Torque Control (DTC) technology is no need to equivalent the model of DC motor, thereby eliminating the vector rotation transform the many complex calculation does not require simulation of DC motor control, and does not need to be simplified for decoupling and the AC motors mathematical model. Simple structure, it can have a very fast dynamic response. Therefore, this article wills shearer direct torque controls system as a research topic. Main topics rectifier and inverter can be divided into two parts. Rectifier using reversible side PWM rectifier; inverter portion direct torque control programmed.Firstly, against the AC speed control system of shearer, analysis constant power control strategy . Discussed the PWM rectifier's basic principle in detail, uses the vector control strategy to the reversible three-phase voltage PWM rectifier. By using Matlab, the performance of rectifier's vector control strategy is researched roundly and systemically including system stable and dynamic state. And based on TMS320LF2407 DSP, the system's hardware and software are designed.Besides, introduces the basic structure and the working principle of the Direct Torque Control system of asynchronous motor. Based on the control system of circular flux linkage track and combined with the characteristics of the mine hoist speed regulating system, a simulation model which can directly control the speed regulating system of the torque is made by MATLAB6.5/Simulink5.0 with use of the flux linkage observation model and the torque observation model in the asynchronous motor'sα-βcoordinate system, proposed the measure ofreducing the system torque pulsation.