Derivation of optimal rotor topologies for consequent-pole PMSM by ON/OFF method

Consequent-pole permanent magnet synchronous machines (CP-PMSMs) have attracted considerable interest as a means of reducing manufacturing costs through a marked reduction in the volume of permanent magnet required to meet a particular torque specification. In this paper, novel rotor topologies for a CP-PMSM are derived to unlock the full design space potential. The ON/OFF method is introduced to manage the laminated steel material distribution over the rotor region, high average torque and low torque ripple are the objects of rotor design, and the immune algorithm is used to search for the optimal material distribution for the formulated problem. More than 9000 different rotor topologies are created and evaluated within 12 hours by this methodology. The optimal topologies under different design strategy are presented, and performance of these topologies are analyzed. The analysis results show that the proposed methodology can deliver novel rotor topologies for the CP-PMSM with surprising torque quality since the torque ripple is suppressed to a low level with no average torque sacrifice.