Determination of the performance parameters of a gearless direct-drive inner-rotor PMBLDC motor via different slot-magnet combinations

Abstract

This study primarily includes the electromagnetic and parametric design and performance analysis of a gearless direct-drive permanent magnet brushless direct current motor (IPMBLDC-DD) with an inner-rotor structure designed as the traction motor of electric vehicles. In IPMBLDC motor design, combinatorial analysis of stator slot geometry and rotor magnet types that affect performance parameters and cogging torque is performed. In this analysis, a maximum output power of 8 kW C motor prototype was used. In the study, firstly, 3 different stator slot geometries of the motor and the parameters of these slots were obtained. Secondly, the effects of 12 different power densities (N28-N55) types of NdFeB magnets in the rotor, which are preferred in PM electrical machines due to their superior properties such as strong strength and high moment/inertia ratio, on the motor performance parameters were determined by combining the specified slot geometries. Dimensional data were obtained at three different operating temperatures (20 & DEG;C-60 & DEG;C-100 & DEG;C) of these magnet types. Finally, it was determined in which combination the cogging torque affected by both the stator slot structure and the rotor magnets took the minimum value. Ansys EM using the FEM performed motor electromagnetic analyses. The values obtained as a result of the analysis were experimentally verified by comparing them with the production values of the motor with the same power. This study will provide a dataset that can be used by a designer who needs detailed information to analyze and develop IPMBLDC motor designs.