A Technique of Torque Ripple Reduction in Interior Permanent Magnet Synchronous Motor

One of the advantages of interior permanent magnet synchronous motors compared to surface permanent magnet synchronous motors is its convenience when modifying the air gap flux density of permanent magnets. This paper introduces a technique of torque ripple reduction by modifying the shape of the rotor to modify the air gap flux density. Three types of rotor surfaces, such as conventional round, slightly cut, and smoothed cut shape, are investigated. The average torque, torque ripple, cogging torque, phase back-EMF, and air gap flux density distribution are analyzed and compared through finite element analysis (FEA). The validity of the proposed model is also verified by comparison between analysis results and measured results.