Performance Review of Permanent Magnet assisted Synchronous Reluctance Traction Motor Designs

This paper presents a detailed performance review of permanent magnet assisted synchronous reluctance motors (PMa-SynRMs) designed for traction applications. As the machine design innovations favor towards reduced and elimination of permanent magnets, PMa-SynRMs are the most trending traction motors in the industry recently. However, extensive designs have been proposed for reduced permanent magnet motor designs such as PMa-SynRMs. In addition, to solve their design challenges such as requirement to generate higher torque density with lower torque pulsations, several multi-objective optimization techniques have been implemented. This study presents a generalized design procedure for the optimal choice of PMa-SynRM specifications apposite to the traction motor designs. A series of two internal and two external rotor multi-phase PMa-SynRMs are optimally designed to use reduced permanent magnets and generate higher average torque with minimum torque ripple. In addition, advantages of adapting five-phases over conventional three-phase PMa-SynRM designs are highlighted. Experiments have been carried out on the prototypes to present comparisons between the 4 traction motor designs considered.