Analysis of A Novel Phase-Unit Axial-Modular Permanent Magnet Machine With E-Core Stators for Electric Aircraft Propulsion System

Nowadays, fault tolerant design is essential for the electric aircraft propulsion system, where the modular design is an effective approach to achieve good fault-tolerance for electric motors. In this article, a novel phase-unit axial-modular (PUAM) permanent magnet machine with E-core stators is proposed and investigated for the propulsion system. The stator of the PUAM machine is totally composed of multiple E-core modules, which are distributed in both axial and circumferential directions, so that it can feature with good fault-tolerant capability, especially when the short-circuit fault occurs in one random stator module. In addition, different from the 2-dimensional (2D) conventional machines, for PUAM machines, all phases are distributed along the axial direction with a fixed mechanical angle and composed of the 3D modules, so that it has the better physical, heat, electric, and magnetic isolations between the phase-to-phase module and unit-to-unit module. Moreover, this PUAM topology can achieve integral-slot non-overlapping concentrated windings (ISNCWs), which has not developed in the conventional electrical machines. The comparison between proposed PUAM machine with E-core stators and conventional machine is also conducted. Finally, the proposed PUAM prototype was manufactured and tested, which can validate the theoretical analysis and finite-element analysis (FEA). This paper aims to propose a novel modular PM machine topology with good fault tolerance for electric propulsion system.