Fault Tolerant 7-phase Hybrid Excitation Permanent Magnet Machine

Abstract

This paper presents a novel 7-phase hybrid excitation permanent magnet (HEPM) machine with three rotors around one stator. Two rotors with PMs axially magnetized and the third rotor with PMs radially magnetized. Thanks to the addition of the third rotor, the inactive end-windings in the configuration with two rotors are then becoming active with a contribution to the torque with an increase of 30%. The impact of the third rotor on the torque density and on the pulsating torques is presented. The fault-tolerant characteristics of the proposed machine are also presented, which proves the interests of this machine for low speed applications.