A Study on an IPMSM Designed to Secure Rotor Reliability in View of Demagnetization

Abstract

The high-capacity traction motor for railway vehicles calls for a high output density, which necessitates using a Neodymium magnet that has a high energy density. Also, any failure in the inverter may lead to high current. Due to the high Current, or the reverse magnetic field, the permanent magnet is subjected to demagnetization. Specifically, a new demagnetization curve called a recoil line is generated, resulting in permanent demagnetization. Thus, the demagnetization characteristics were analyzed in light of the recoil line. Based on a calculation scenario demagnetization was predicted via the back EMF, and the final model was derived. In addition, performance and temperature saturation tests were performed for verification.