Design and simulation of controller for medium voltage thyristorised induction motor soft starter

Soft starters are used with induction motors in blowers, fans, pumps and the crane hoist drives. AC voltage controllers are used as soft starters in induction motors for starting and to adjust its speed. This paper presents a novel topology for ac voltage controller to generate the firing pulses for appropriate thyristors for any given operating torque, speed of the motor and the load. Simulation results presented in this paper explain the advantages of proposed soft starting method over conventional method. The advantages of proposed method are its simplicity, accuracy and fast response.