Design and Analysis of Different Rotor Structures In-Wheel Brushless DC Motor Performance for Electric Vehicle Applications

The BLDC In-wheel motors are increasingly preferred for low-power electric vehicle applications due to their highly efficient mechanical energy conversion, high torque, and low maintenance compared to conventional BLDC motors. Additionally, they offer smooth operation, regenerative braking, and easy speed control. However, a key challenge in designing the rotor structure for in-wheel motors is managing heat, which can affect efficiency, and reliability, and lead to premature issues. This paper analyzes three different rotor flux barrier and skewing techniques aimed at minimizing losses and torque ripples. These techniques include surface-mounted radial magnets, surface-mounted parallel magnets, and surface-mounted multilayer radial magnets. Optimal geometry parameters are derived and calculated using sizing equations. A finite element model is employed to analyze motor solve software and study characteristics such as cogging torque, losses, and magnetic field strength. Simulation results demonstrate that the interior rotor curved magnet in-wheel motor enhances performance to meet the requirements for low-power electric vehicles. The surface-mounted radial magnet rotor structure achieves less cogging torque and high efficiency for in-wheel motor EV applications.

I. Introduction

In-wheel brushless DC (BLDC) motors have gained traction in electric vehicle (EV) applications due to several potential advantages such as increased efficiency, compact design, and improved vehicle dynamics [1]. Different rotor modifications, such as surface-mounted magnets with radial or parallel configurations, can impact various aspects of motor performance, including torque output, efficiency, and thermal management [2]. Analysing the performance of cogging torque, speed-torque characteristics, efficiency, and back electromotive force (EMF) in in-wheel BLDC motors is extremely useful for EV applications.