Anisotropic Magnetic Core for the Iron Loss Reduction of Permanent Magnet Synchronous Motor

Abstract

An interior permanent magnet synchronous motor (IPMSM) using a stator core made of grain-oriented (GO) anisotropic magnetic material is manufactured to evaluate the potential iron loss reduction that GO can bring compared to the conventionally used non-oriented (NO) quasi-isotropic silicon steel. The stator core is divided into yoke and teeth pieces that are arranged so that the GO material easy magnetization direction follows the main magnetic flux that flows in the core during the motor operation. The motor iron loss is measured under two conditions: 1) the IPMSM is rotated by an external motor ("drag force operation"), 2) the IPMSM is driven by a pulse-width modulation (PWM) inverter without load ("no-load operation"). The manufactured motor shows 13.5 % iron loss reduction during drag force operation and 5 % reduction during no-load operation. Numerical calculation is also carried out by 2-D finite element analysis (FEA) to confirm the experimental data.

Analysis of Flux Density and Iron Loss Distributions in Segmented Magnetic Circuits Made With Mixed Electrical Steel Grades

“…The prototype improves the saliency ratio by 47% and thus the torquecurrent characteristic compared to a conventional NOES rotor. In [5] [27] [28], the authors have studied and realized a GOES PM stator fully segmented, where the RD of the sheet is maintained in the direction of the field lines in the yoke and in the tooth (Fig. 14).…”