Torque quality and comparison of internal and external rotor axial flux surface-magnet disc machines

In this paper, pulsating torque components of PM machines and pulsating torque minimization techniques are discussed for axial flux surface magnet disc type PM machines. The pulsating torque analysis describing general instantaneous electromagnetic torque equation and torque ripple factor (TRF) is briefly given in order to analyze ripple torque of the machines. A detailed finite element analysis (FEA) focusing on the minimization of cogging and ripple torque components using some techniques are also provided. A detailed comparison of the two techniques is also illustrated in the paper.