Reduction of Rotor Loss and Torque Ripple in an IPMSM using Magnetic Wedges

An interior permanent magnet synchronous motor (IPMSM) is characterized by a high-efficiency in wide-range of operations. However, when driven at high speed, rotor loss and torque ripple occur due to the spatial harmonics generated by air-gap permeance fluctuations. In this study, a finite element analysis (FEA) is used to clarify the loss and torque ripple reduction using a magnetic wedge. Results obtained showed that the rotor loss and torque ripple was reduced by 30.4% and 14.0%, respectively, after inserting magnetic wedges made from a magnetic composite material with extremely small iron loss.