Comparison of Nonoriented and Grain-Oriented Material in an Axial Flux Permanent-Magnet Machine

Abstract

The performance and iron losses of an axial flux permanent-magnet synchronous machine (AFPMSM) using nonoriented (NO) steel are compared with the performance and iron losses of an AFPMSM using grain-oriented (GO) material. The machine is modeled by several 2-D finite element models in circumferential direction, at different radii. The material model for the GO material is an anhysteretic anisotropic model based on the magnetic energy. The magnetic energy is computed by using several measured quasi-static -loops on an Epstein frame in seven directions starting from the rolling direction to the transverse direction. The losses are calculated a posteriori, based on the principles of loss separation and dynamic loop measurements. A loss model was made for each of the seven directions, assuming unidirectional fields. In comparison with the more usual NO material, both the saturation induction and the torque are higher with GO material. The magnetic field in the GO material is lower than for NO material in the major part of the iron, but higher in the tooth tips where the field is not in the rolling direction. The stator iron losses are about 7 times lower for the considered GO compared to the NO material.

Comparison of Iron Loss Models for Electrical Machines With Different Frequency Domain and Time Domain Methods for Excess Loss Prediction

“…Both parameters can be fitted in the frequency and time domain on the basis of iron loss measurements for a range of frequencies and peak induction values. The fitting method in the frequency domain can be found in [5] and is later described in this paper. It is shown how significant is the error introduced using the material parameters fitted in the frequency domain to estimate the losses in the time domain model.…”

A Computationally Efficient Method to Determine Iron and Magnet Losses in VSI-PWM Fed Axial Flux Permanent Magnet Synchronous Machines

“…The considered axial flux machine does not have a stator yoke, so that rotational fields occur only in the tooth tips. It was shown in the paper [25] that this region is limited.…”

Magnetic Materials Used in Electrical Machines: A Comparison and Selection Guide for Early Machine Design

“…In contrast, rotational electrical machines mainly use non-oriented materials since the flux direction is generally not unidirectional but changes direction (it rotates in the stator yoke). In large electrical machines, where the stator is constructed of several yoke parts, or in research projects dedicated to smaller electrical machine topologies, such as axial-flux machines, grain-oriented SiFe material might be used as well [13]- [15]. However, the vast majority of electrical machines are manufactured from non-oriented grades.…”