Design Optimization and Experimental Study of Coreless Axial-flux PM Machines with Wave Winding PCB Stators

This paper presents a systematic design optimization and experimental study of coreless axial-flux permanent magnet (AFPM) machines with wave winding printed circuit board (PCB) stators. Existing PCB winding configurations are briefly reviewed and compared to serve as a performance reference. A new concept –the “macro coil”– is proposed to model PCB stator windings in 3D finite element analysis (FEA) to facilitate large-scale multi-objective optimization with the winding eddy current losses evaluated in each design candidate. The detailed trace-by-trace model for a selected optimal design is then built to check the voltage difference between parallel paths and the resulting circulating currents. A prototype with two PM rotors and a central stator comprising multiple stacked PCBs has been fabricated and tested on a customized test fixture for experimental validation.