Effect of stator winding connection on performance of five-phase linear induction machines

Abstract

In electric traction, Linear Induction Motors (LIMs) have become a competitive alternative, especially for low speed applications where machines with short stators are commonly used. Due to driving dynamics tolerances, LIMs are characterized by their relatively high magnetizing current. Employing multiphase stator winding design may be a viable technique to reduce the current per phase, which reduces the stress on the power electronics converter. Moreover, due to the open-ended construction of the linear motors, the phase currents in LIM experience a notable degree of unbalance even under a balanced supply. Therefore, the additional degrees of freedom offered by multiphase systems can be exploited to ensure balanced stator currents, which expectedly improves the overall machine performance. In the available literature and for rotary induction motors, the stator winding connection of a multiphase machine has shown a notable impact on the machine performance under fault conditions. In this paper, the effect of stator connection on the performance of a five-phase LIM is investigated. A five-phase prototype LIM is designed and simulated using 2D finite element simulations. Experimental verification is also provided to validate the theoretical findings. The introduced study compares two connections, namely, star and pentagon connections under both healthy and open-phase cases. 2016, Institution of Engineering and Technology. All rights reserved.