Permanent magnet BLDC Motor designs with skewing for torque ripple and cogging torque reduction

Permanent magnet BLDC motor can bedesigned with different rotor configurations based on thearrangement of the permanent magnets. Rotorconfigurations strongly influence the performance ofpermanent magnet electrical machines. The aim of thispaper is to compare and evaluate different rotorconfigurations for PMBLDC motor with or without skewed stator slot. Most of theapplications prefer surface mounted permanent magnetdesign due to its ease of construction and maintenance in [1,2]. FE methods have been used for analysis andcomparison of differentgeometry parameters and configurations in [3,4,5]. This paper describes a comprihensive design of a three phase PMBLDC motor 35 kW for electrical drive application.An optimal design of PMBLDC motor have been implemented by analytical and simulation methods. In this paper, skewing slot is applied to the PM surface mounted Brushless DC Motor for eliminating torque ripples. To observe the skewing effect, the stator lamination layers are skewed with different angles. The best skewing angle is determined by number of stator slots and cogging period with a parametrical study. With determined skewing angle, the cogging torque eliminated theoretically and flux density space harmonics are also reduced.