A simple core structure for small axial-flux PMSGs

This paper presents the performance of a 375W axial-flux generator with a parallel-teeth stator core. One of the main set-backs in AFPM machines is the manufacture of stator steel cores. This can be solved by adopting a yokeless parallel-teeth stator. This stator structure is discussed and its performance is compared with the trapezoidal-teeth topology. The two configurations are analyzed in FEA and their performances are in agreement. Their back-EMFs and efficiencies were 17V and 82% respectively. In addition the parallel-teeth stator topology reduces cogging torque inherently. Its tooth-structure is modular in design which eases the rewinding of coils. Experimental results on back-EMF, voltage regulation and efficiency are also presented, i.e. 17.9V and 15.2V at a rated current of 10A at an efficiency of 80%. Further FEA analysis on torque ripple performance, experimental results on the segregation of core losses and EMF harmonics and temperature response of the machine are included in the paper.