Abstract: In consideration of hydraulic automatic take-ups for belt conveyor’s various malfunction ,such as, high failure of hydraulic equipment, slow reaction rate ,etc，put forward a new kind of variable frequency automatic take-ups.The new kind take-up is only made up of electromechanical components, which greatly simplifies the system structure.Apply Space Vector Pulse Width Modulation technology (SVPWM) to Permanent Magnet Synchronous Motor (PMSM) speed control system,in order to control the winch’s speed and steering,then adjust the conveyor belt tension.Establish the system’s mathematical model and simulation model. Use AMESim and Matlab tool to make the simulation analysis on the dynamic characteristics of belt conveyor. The results show that the loose edge tension of driving drum remain at around 75kN in controlled start-up stage and around 52kN in stable operation and outage stage,which can adjust the belt tension timely and meet the need of various conditions of belt conveyors.