Rotor losses and efficiency of the high-speed BLDC motor with a rotor covered by Kevlar fiber and resin

Abstract

Rotor losses are often neglected in the analysis of high-speed BLDC motors due to the small number of turns and the weak armature reaction. However, it turns out that along with increasing load and stator current the rotor losses play a significant role in the overall loss distribution. As a result, the electromagnetic torque, the excitation factor, and the efficiency of the motor are reduced. Moreover, the phase electromotive forces are deformed as a result of the armature reaction phenomena.