Direct Torque Control Of Double Fed Motor Used In Mine Hoist

Variable-frequency speed control system of double-fed motor can double the output power of the motor in the scope of double-speed. This is the advantage that other electric drive system does not have. This paper which study the theory, control structure, simulation and experimental verification of double-fed motor speed control system in mine hoist is based on direct torque control strategy.This paper first discusses the theory of variable-frequency speed control system of double-fed motor in the scope of double-speed,drawing a conclusion that variable-frequency speed control system of double-fed motor can double the output power of the motor in the scope of double-speed. Then, analyzing the theory of PWM rectifier in front of AC-DC-AC frequency converter which connect rotor, presenting a mathematical model based on vector control. Accordingly, vector control structure of double closed loop PWM rectifier is given, simulation results show that, the mathematical model and vector control structure is correct and feasible. This thesis emphasizes on the theory of double-fed motor speed control system in mine hoist based on direct torque control strategy,giving a mathematical model of double-fed motor in dq-coordinate of rotor.Meanwhile, the structure and switch status table that based on this mathematical model which of direct torque control used in double-fed motor speed control system is presented. Simulation results show that, the given mathematical model and control structure is correct. The structure of compound control system meetting the lifting methods is given at the same time. At last, The experimental verification is introduced.This paper provides a new study way for the scheme of electrical driven system in mine hoist,and it has good prospects for industrial applications.