Design and Loss Analysis of Axial Flux Permanent Magnet Synchronous Motor with PCB Distributed Winding

The direct current ohmic loss and eddy current loss of copper conductors are determined by the structure and parameters of printed circuit board (PCB) winding, for axial flux permanent magnet synchronous motor with coreless PCB stator. This paper presents a type of PCB nonoverlapping distributed winding, which makes the most of PCB space. Based on fundamental theories, the general expression of PCB distributed winding resistance and loss is derived by the analytical method, which can be used to achieve the fast estimation in the initial design and optimization of PCB stator. To improve the efficiency of designed PCB axial flux permanent magnet machine, the optimal width of the active conductor is further studied, and the critical frequency which can balance DC ohmic loss and eddy current loss of PCB winding is proposed. A part of analytic calculation results is verified by 3D finite element analysis (FEA). Lastly, a 300 r/min, 240 W prototype machine with PCB stator is manufactured and implemented, considering the environment temperature and internal temperature of the machine, the resistance and losses of the PCB winding under different frequencies and currents are experimentally validated.