Effects of Reaction Field Caused by Eddy Currents and Hysteresis Phenomenon in Laminated Cores on Torque Characteristics of Interior Permanent Magnet Synchronous Motors

In this article, we investigate the effects of reaction fields caused by eddy currents and hysteresis phenomenon in laminated cores on torque characteristics of interior permanent magnet synchronous motors (IPMSMs) applied to variable speed applications. Both the average torque and torque ripples are decomposed into terms produced by harmonic air-gap flux densities by using finite element analysis (FEA) that considers the reaction fields in laminated cores. It is clarified that the torque decrease under flux weakening control at high speeds is not negligible.