Open-Leg Fault-Tolerant Control and Comparative Postfault Performance Analysis for Five-Phase Series-End Winding PMSM

Compared with the Y-connection topology in five-phase motor drive, the open-leg fault will lead to unique postfault characteristics in series-end winding (SEW) topology, for which the most common used winding connection sequence (WCS) of ADBEC will lose the advantage of large speed range. This article newly proposes the open-leg fault-tolerant control for five-phase SEW permanent-magnet synchronous motor. First, the open-leg fault is divided into two types in SEW topology. For the type II fault, in terms of different postfault targets such as minimum copper loss and maximum torque, the harmonic current references are firstly derived for different WCSs. Then, the voltage compensation scheme is adopted to achieve the desired fault-tolerant currents. Subsequently, the postfault performance indicators are comparatively analyzed across different WCSs. It is concluded that under type II faulty condition, WCS of ABCDE can achieve the smaller fault-tolerant currents, less copper loss and same speed range comparing with ADBEC. In addition, the postfault performances of both type I and II faults are also theoretically compared with Y-connection and pentagon topologies. The experimental results are presented to verify the analysis and the conclusions, which can provide more basis for selecting which WCS in practical application of SEW topology.