An investigation of advanced magnetic materials for axial field brushless permanent magnet motor drives for automotive applications

This paper investigates the operating characteristics of two emerging magnetic materials, amorphous magnetic material and soft magnetic composite, and aims to address specifically the iron losses in inverter-driven high speed electric machines for automotive applications. In the paper, a three phase brushless axial field permanent magnet machine is considered due to its compact shape and its high torque, power density and efficiency. 3D finite element analysis (FEA) was used to model and analyze axial field machines that utilize such magnetic materials. A cut version of amorphous magnetic material has been used successfully in the stator, and a direct comparison of amorphous magnetic material and soft magnetic composite stators are also given. The paper presents detailed test results to examine the influence of rotor magnet design, magnet type and air gap length, and provides the performance characteristics of the motor configuration, including drive and motor efficiencies. In addition, a number of motor parameters were simulated using the 3D FE analysis tool, including back-EMF profile and cogging torque.