Study on Designing 350 W-Class MG-PMSMs for Robot Joint Actuators to Apply Robot Technology to Railway Maintenance Systems

This study addresses technology that can realize non-contact power transmission by applying magnetic-geared permanent magnet synchronous motors (MG-PMSM) encompassing the functions of mechanical reduction gears, through single actuators, to robot joints for diverse maintenance systems in the railway field. In order to derive basic models that take into consideration design requirements so as to apply MG-PMSMs to geared motor drives encompassing PMSMs and mechanical reduction gears for existing railway maintenance robot joints, design techniques for minimizing air-gap flux imbalance and torque ripples in dual air-gaps were studied, and diverse combinations of the number of inner rotor PM poles (IP)-number of pole-pieces (PP)-number of outer stator PM poles (SP)-number of stator slots (S) that would make possible design for basic models of 350 W-class MG-PMSMs were derived. For each of the derived combinations, 12 cases of basic models of 350 W-class MG-PMSMs were derived through the optimization of design variables so as to minimize air-gap flux imbalance and torque ripples, and, through electromagnetic characteristics and size analysis, the final model with high output power density for 350 W-class MG-PMSMs was selected.