Mechanical design considerations of Halbach-array rotor for a new ironless stator axial-flux PM machine

This paper focuses on the mechanical design and static strength analysis of permanent magnet (PM) Halbach array configuration for ironless stator axial-flux PM machine. Finite element analysis of electromagnetic field is used to verify the severity of attractive force between twin rotors and the complexity of repulsive force among PM segments of Halbach array. These not only cause difficulty during assembly of PMs and rotors, but also influence integrity design of rotor for high-speed operation. In order to solve the problems above, two kinds of rotors with different installation methods of PMs are comparatively analyzed by finite element method. The strain and deformation of each part for two kinds of rotors are confirmed to locate the reason for the fracture of PMs with the original rotor design. Based on FEA model, a new rotor design and optimization are undertaken to validate the mechanical construction.