Separation and comparison of average torque in five‐phase IPM machines with distributed and fractional slot concentrated windings

Abstract

This study proposes a method to separate average permanent magnet (PM) torque and average reluctance torque of five-phase interior permanent magnet (IPM) machine based on transient finite element method (FEM). The key of this method is to count total torque as four torque components by considering the saturation and cross-magnetisation between d – q axes, and every torque components are calculated from d–q axes parameters directly. The parameters in d–q axes reference frame are transformed from ABCDE reference frame via five-phase Park transformation. Comparing with the existing methods, the proposed method maintains the same accuracy while time saving because d–q axes parameters can be obtained directly by one-time FEM simulation. Meanwhile, the proposed method is adopted to separate the PM torque and reluctance torque from two five-phase IPM machines with fractional-slot concentrated winding (FSCW) and integral-slot distributed winding (ISDW). Finally, the FEM and experimental results show that the IPM machine with FSCW produces lower reluctance torque ratio than that of IPM machine with ISDW. Besides, the results demonstrate that the flux-weakening performance connects with characteristic current (Ψ PM d / Ldd ) strongly.