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Surface Mounted Permanent Magnet Synchronous Machine

Omar Laldin, Ampaire, Inc.

This model recreates the SM-PMSM published in [1]. The machine is random-wound; therefore slot conductors are represented in a homogenized way. An analytical model and test data for this machine are presented in [1]. The results are shown to match those obtained from the analytical model when saturation is ignored, and from test data when saturation is considered. The machine losses are presently ignored.

The Torque study obtains a torque waveform over rotation of one slot for a given current command, as calculated from flux linkages. The average torque produced may subsequently be obtained. It is noted that, being an overall machine energy-based evaluation (within FEA), this study is not expected to result in an accurate representation of torque ripple over the slot (which would require a significantly higher number of air-gap mesh elements, as well as convergence on the torque obtained from Maxwell Stress Tensor). It is, however, expected to provide an accurate value for average torque and flux linkages in the q- and d-axes.

Setting the current command to approximately zero and the Iron behavior to linear steel using "relative permeability", the average d-axis flux linkage due to the magnet is found to be in reasonable agreement with the analytical model results shown in Section IX of [1]. Setting the Iron behavior to nonlinear steel using "HB curve" results in an average d-axis flux linkage value in agreement with experimental data shown in Table II of [1].

The FluxLinkageMap study sweeps the current magnitude and angle, as well as rotor position over one slot. A flux linkage map is then obtained as a function of current magnitude and angle by averaging the values over one slot of rotor positions.

[1] B. N. Cassimere, S. D. Sudhoff, D. H. Sudhoff, "Analytical Design Model for Surface-Mounted Permanent-Magnet Synchronous Machines", IEEE Transactions on Energy Conversion, v. 24, no. 2, June 2009.

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