Analysis and design of a PM Brushless Motor for high-speed operations

This paper deals with the design of a 1-kW permanent-magnet (PM) brushless motor operating in the speed range of 20-40 k r/min. The design procedure involves a parametrical investigation of the most adequate motor configuration by means of a coupled thermal and electromagnetic analysis. The design procedure takes advantage of an analytical study based on Maxwell's equations and is refined by finite-element analysis. Both slotted and slotless motor configurations have been taken into account, with different PM materials for an overall comparison of the motor performance.