electric motor, energy efficiency, finite element analysis, permanent magnet motors, traction motors
Abstract
Research and innovations to reduce the environmental impacts related to carbon dioxide emissions have been attractive in the last decades. Replacing internal combustion motors with electric motors in viable applications can help with climate change. It can reduce the dependence on fossil fuels, contributing to the improvement of air quality and enabling the use of renewable energy sources. Permanent magnet synchronous motors (PMSMs) are required to achieve high energy efficiency. It is possible to choose between internal and external rotors considering the topology. Generally, this decision is associated with the constructive characteristics of the application. In the case of electric traction, the external rotor option becomes attractive when the motor is coupled directly to the wheel. However, considering the sustainability approach, the internal and external rotor topologies should be investigated. This work presents loss comparisons to understand the best option focused on high efficiency and minimum raw material to specific requirements. The methodology includes technical definitions and calculations using analytical equations and Elmer software based on the finite element method. The external rotor machine is used as a reference and compared to an optimized design with the internal rotor. According to this work and rated conditions, the electrical efficiency with the internal rotor increased by around 2%. The mass was reduced by approximately 22% compared to the motor with an external rotor.
