Stator and Rotor Shape Designs of Interior Permanent Magnet Type Brushless DC Motor for Reducing Torque Fluctuation

This paper presents the stator and rotor shape designs in interior permanent magnet (IPM) type brushless dc (BLDC) motor for reducing torque fluctuation. The partly enlarged air-gap made by rotor unequal out diameter and stator core structure with pole shoe modification is introduced. The torque ripple reduction is achieved by upgrading torque value at minimum torque position and their detail characteristics are compared. The final stator and rotor shape of IPM type BLDC motor is decided by design of experiments (DOE) process. The magnetic field and torque characteristics are analyzed by 2 dimensional (2D) finite element analysis (FEA) and their performances are validated by experimental results.