Comparative Electromagnetic Analysis of Outer Rotor BLDC Motor Considering Different Design Parameters

Abstract

This study presents a comprehensive electromagnetic analysis of an outer rotor Brushless DC (BLDC) motor considering different design parameters using Finite Element Method (FEM)-based simulations in ANSYS Maxwell 2D. The motor is designed by varying key parameters such as rotor pole number, slot number, magnet thickness, and magnet type to investigate their effects on the motor performance. The performance of each configuration is evaluated in terms of air-gap flux density, cogging torque, efficiency, output torque, and output power. The results show that increasing the pole number improves low-speed torque capability, while moderate pole configurations provide better overall efficiency. The number of the slots is found to significantly affect the cogging torque and flux distribution, where appropriate slot-pole combinations reduce the torque ripple and improve the motor performance. In addition, magnet thickness and magnet type directly influence the air-gap flux density and torque production. It is observed that increasing magnet thickness does not always enhance performance due to saturation and flux leakage effects, and certain configurations lead to reduced the cogging torque. Consequently, the results show that an optimal BLDC motor design requires a balanced selection of the pole number, slot configuration, and magnet properties. © 2026 IEEE.