Extended Operating Range of Induction Machines Using Switched Stator Windings

Induction machines are widely used in many applications, and they are attractive for traction applications as well. However, a machine may not achieve the desired operating range under given boundary conditions of a drive train system. Several methods have been examined in literature that aim to extend the operating range, for example, star-delta-switching or pole-amplitude modulation. In this work, the influence of different winding configurations of an existing induction machine is investigated considering their potential for operating-range enhancement. Ultimately, none of the configurations is able to meet all the requirements due to, for example, current or voltage limitations. Therefore, alternative methods are investigated in this work and, finally, switched stator windings, also called series to parallel switchover, are employed to combine the advantages as well as the operating ranges of two single winding configurations. The simulation as well as experimental results show a considerably extended operating range especially at higher speeds and prove the feasibility of the proposed method.