Torque density improvements for high performance machines

In this paper, the main aim is to propose and investigate possible methods for extending and improving the torque density capabilities of high performance, electrical machines. This is achieved by combining performance enhancing strategies such as the use of an outer rotor, the use of cobalt iron laminations and the adoption of high performance winding arrangements into a structured methodology that details the potential improvements step by step. A main point of interest of this paper is the permanent magnet demagnetisation analysis, resulting in the adoption of an optimum arrangement of a five stage, full-Halbach array. The above is presented in terms of an electrical machine used as an in-wheel motor in an aircraft traction application.