A Novel Phase-Unit Axial-Modular Permanent Magnet Machine With U-Core Stators for Aerospace Propulsion System

In this article, a novel phase-unit axial-modular (PUAM) permanent magnet machine (PMM) with multiple U-core stators is proposed for aerospace propulsion system. The stator of this PUAM machine is completely composed of U-core stator modules, which can be physically isolated and easily be replaced when the fault occurs. Firstly, the topology and basic working principle are illustrated and investigated. Secondly, the magnetic field distribution of this proposed machine is analyzed, and the differences among all the candidates are targeted. The magnetic field harmonics are also compared. Thirdly, the performance comparison between the PUAM machine and other models is conducted, e.g., no-load back-EMF, output torque, power factor, flux weakening ability, losses, efficiencies, etc. This comparison can exhibit the advantages of the proposed PUAM machine with U-core stators, i.e., superior torque and flux weakening capability, lower core loss and higher efficiency. Finally, a PUAM prototype was manufactured and tested to validate the theoretical analysis by finite-element analysis (FEA). In addition, the experimental results can agree well with the theoretical analysis and FEA.