Abstract
As the oil shortage is worsening gradually, electric scooters are attracting more attention and getting more popular in application. Many companies started research projects and even production of these scooters. Hence, electric scooters will become a transportation tool with convenience and green energy considerations. In this thesis, a high-performance, low-cost and compact electric motor would be investigated for the electric scooters. The objective is to study and design a highly efficient brushless DC motor with internal permanent magnets which are high-performance NdFeB magnets. The magnets are high in energy, magnetic retentivity, and coercivity so that the air-gap magnetic flux density inside the motor can be increased. With the goal for utilization of reluctance torque to reduce the weight and volume, this study first gathered the specifications of the scooters; and then, we design the motors based upon fundamental formulae for the sizes of the motors. We further used computer simulation tools for analysis of the magnetic circuit in details. Finally, we finished the design with data from two-dimensional magnetic field distributions of many cases with optimized parameters of the motors. By exploring the details and comparing the pros and cons from the simulations, we concluded that the design goals for electric motors in application for electric scooters have been met.