May 2017: Slotless airgap winding PMSM, notches, measurement services

MANATEE new features

MANATEE (Magnetic Acoustic Noise Analysis Tool for Electrical Engineering) software logo

Slotless airgap winding PMSM can now be studied in MANATEE. All electromagnetic models (FEMM, subdomain, permeance magnetomotive force) have been extended to model this new topology.

The following figure illustrates the radial & tangential airgap flux density due to a one pole distributed winding armature field, either computed numerically with FEMM or semi-analytically with subdomain models. The subdomain model calculates the full field distribution (2048 steps along airgap, 2048 steps in time) in a fraction of a second.

Radial and Tangential Airgap Flux (Femm vs subdomain)
Radial and Tangential Airgap Flux (Femm vs subdomain)

MANATEE 1.06.03 will also include the following changes:

- The theoretical analysis of magnetic force harmonics and order tracking analysis have been extended to outer rotor simulation
- The optimization plots have been improved (e.g. plot of correlation factors)
- An acoustic radiation factor model for a flat plate has been introduced

Zoom on MANATEE features


The effect of notches can be quickly studied in MANATEE using hybrid modelling techniques. The effect of notches can be studied accurately by evaluating the permeance function using FEMM. This is fully automated in MANATEE as shown in the squirrel cage induction machine tutorial focusing on noise minimization using rotor notches. (This tutorial will be added to MANATEE 1.06.03).

Structural mode contribution (without and with the notches)
Structural mode contribution (without and with the notches)

Zoom on EOMYS services

Besides modeling, simulation and optimization consulting work on electric machines, EOMYS team can run complete vibroacoustic tests focusing on NVH due to magnetic forces in a semi-anechoic or industrial environment. In addition to microphones and accelerometers, EOMYS equipment include miniature accelerometers and a telemetry-based acquisition system dedicated to the analysis of outer rotor machines.

EOMYS experimental measurements

Publication of the Month

G. Y. Zhou; J. X. Shen, "Rotor Notching for Electromagnetic Noise Reduction of Induction Motors," in IEEE Transactions on Industry Applications , vol.PP, no.99, pp.1-1

This publication demonstrates how notches can be used on rotor lamination to reduce the magnetic noise of an induction machine of 5 dB.

If correctly sized, notches at tooth tips can indeed artificially increase the equivalent slot number, reducing harmonic forces to the first rank of permeance harmonics. The main excitations are therefore shifted to higher frequencies. In induction machine, rotor notches have both an impact on force frequencies and wavenumbers, while stator notches only affect force wavenumbers, which make them less efficient to solve "electrical noise" issues.

The effect of notches can be studied in MANATEE electromagnetic and vibroacoustic environment as shown in the induction machine tutorial.

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