Soft starting method for single-phase PWM AC chopper fed three-phase induction motor

This paper presents a soft starting method for a three phase induction motor operating from a single-phase PWM AC chopper in order to reduce high starting current caused by direct on line (DOL) starting. The MATLAB/Simulink is used for simulation. The motor stator windings are connected in a delta form with an external capacitor for operating from a single phase supply. With the proposed method, the initial voltage and ramping of voltage with a desired rate can be adjusted in order to obtain appropriate starting time and starting torque. The results of the simulation show that the motor starting current can be reduced and the capacitor value affects the starting time.