Design optimization of brushless permanent magnet hub motor drive using FEA

Brushless permanent magnet drive is a key technology for electric powered two wheelers. This paper presents a design of a high efficient and high-power-density external rotor, 3-phase brushless permanent magnet dc motor for use in electrically powered two wheelers. Cogging torque reduction methods are applied to optimize the design with the decrease of cogging torque and increase of the developed torque as objective. The air gap length, teeth width, teeth shape and winding configuration are also selected for the design variables respectively. Parasitic effect like unbalanced radial force, easy manufacturability and low process time is also taken into consideration. Static and dynamic characteristics of the motor are obtained using 2D FEA (finite element analysis). With the simulation results, sample motors are fabricated and tested on a electric scooter the experimental results are shown to confirm the validity of the optimization results.