Design and Experimental Validation of a Slotless Axial Flux Permanent Magnet Motor with PCB Windings for Miniaturization

This paper presents the design and experimental validation of a slotless axial flux permanent magnet motor with printed circuit board (PCB) windings, targeting 40 W output and a 30 % reduction in active volume. Pole count, coil count, and number of turns were evaluated under PCB manufacturing constraints. End turn dimensions, overhang configurations, and PCB layer count were examined to balance output power, losses, conductor content, and magnetic air gap length. Corner rounding and multiple vias were applied to lap and wave winding patterns to reduce resistance. The final design reduced the active volume from 57.4 to 40.1 cm³. A prototype was fabricated, and measured phase resistance and no-load back electromotive force were compared with simulations. Load tests confirmed approximately 0.24 N·m torque and over 40 W output. These results provide guidance for compact PCB-winding motors considering manufacturing constraints and electromagnetic characteristics.