Analysis and Performance Evaluation of Radial Flux Air-Cored Permanent Magnet Machines with Concentrated Coils

In this paper two different concentrated coil configurations for radial flux air-cored permanent magnet (RFAPM) machines are analysed and evaluated against a RFAPM machine that utilises overlapping coils. The comparative analysis of the different machines are done analytically. The analytical results are compared with finite element analysis results of simplified linearised equivalent models for the different coil configurations. The finite element analysis results correlate well with the analytical results in predicting a higher torque factor for small diameter, short stack RFAPM machines with concentrated coil configurations than for machines with overlapping coil configurations, with the same coil side-width values.