Reduction in Torque Ripple by Applying an Asymmetric Rotor to PMSM

In this study, an asymmetric rotor was developed to reduce the cogging torque and torque ripple regardless of the rotational direction and its driving point. Specifically, the rotor had a linear symmetric structure for bi-rotation. In addition, a π-shaped pole rotor was proposed as a new structure to alleviate magnetic saturation at the edge parts of the rotor. Optimal design using the Rosenblock method revealed that the proposed structure can reduce the cogging torque and the torque ripple in a wide range of driving conditions.