Design of an outer rotor ferrite assisted synchronous reluctance machine (Fa-SynRM) for electric two wheeler application

Ferrite Magnet assisted Synchronous Reluctance motors (Fa-SynRMs) are preferred for cost sensitive applications that need high efficiency and wide Constant Power Speed Ratio (CPSR). In this paper, a new rotor topology for an outer rotor Fa-SynRM is proposed to achieve high efficiency and wide (CPSR). Multi-objective optimization is performed using Genetic Algorithms (GA) in conjunction with a Finite Element Analysis (FEA) based model to maximize efficiency-constrained CPSR, peak torque and average efficiency for a 1.2 kW electric/hybrid electric two wheeler application. For design studies, rotor structure with pole number between 10 and 16 and stators with different slot numbers with distributed and concentrated windings are considered. Stators are skewed to achieve zero cogging torque and effects of skewing on motor performance are incorporated into the machine model analytically. A 10-pole 48-slot design is chosen from the pareto optimal design set and is prototyped to test the validity of the proposed structure.