Rare-earth magnet reduction on interior PM Motor based on the consequent pole rotor design

This paper focuses on the rare-earth magnet reduction on interior permanent magnet (PM) motor based on the consequent pole rotor design. The motor design is targeted for the two-wheeler traction application with demanded constant power region consideration. The reference design is based on a 6 kW and 8-pole V-shape interior PM (IPM) motor with a constant power region between 3000 rpm and 9000 rpm. This paper develops a guidance for rotor magnet design to minimize the cogging torque while maintaining the torque output. However, due to the asymmetric rotor magnet, the equivalent direct axis flux permeance on consequent pole rotor should be higher than conventional IPM rotor. Because of the reverse saliency whereby the direct axis inductance is greater than the quadrature axis inductance, the better constant power field weakening control is expected. All the design process is verified based on finite element analysis (FEA), and the proof-of-principle prototype is fabricated and verified with the respect of back electromagnetic force (EMF).