Analysis of a novel topology of soft starter for induction motors

To overcome the problems of large lower-order harmonics and slow response associated with conventional thyristor-controlled voltage, self-commutated switches are used for the novel topology. Yet, unlike the soft starters previously reported in the literature, the gating signals of the proposed topology are easier to implement. Moreover, it does not require synchronization with the ac mains and the harmonics of the stator current can be eliminated. The operating principle of the soft starter is analyzed in this paper and the experimental results are given in order to prove the validity of the new topology.