March 2018: noise maps, flux lookup table, skew optimization, external rotor NVH

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

Ongoing MANATEE developments

MANATEE now includes an additional feature to speed up calculation times in variable speed and skewed mode: flux lookup tables, which can be applied to noise map calculation or skew optimization. This feature is compatible with the import of third party electromagnetic FEA software calculations in MANATEE. As an example the following noise map is generated in 2 min of calculation:

Noise map of a 48s8p IPMSM traction machine
Noise map of a 48s8p IPMSM traction machine

Another key ongoing development is the extension of MANATEE models to synchroreluctant machines (SyRM).

Zoom on MANATEE validation case

This validation case EM_SPMSM_NL_028 aims at comparing the subdomain model of a Surface Permanent Magnet Synchronous Machine in open circuit, demagnetization condition (-10% of remanent flux on the pole number 3) to a full finite element analysis run with FEMM. One can see that the subdomain model correctly captures all the flux density harmonics in demagnetized case in 1 sec of calculation, which is much faster compared to finite element analysis on such an asymmetrical problem.

Flux distribution comparison between MANATEE subdomain model and FEMM in case of a locally demagnetized SPMSM

MANATEE is the only simulation software providing fast electromagnetic and vibroacoustic analysis tools in faulty conditions such as eccentricities, uneven airgap, pole displacement and pole demagnetization.

Conferences and Events

EOMYS will present at the 11th International Symposium on Electric and Magnetic Fields, EMF 2018, in Darmstadt, Germany, 12 April 2018, a poster entitled "Fast calculation techniques of airgap flux distribution in electrical machines".

EOMYS will also organize a free technical workshop on the vibroacoustic design of electrical machines on Friday 13th of April, 2018 in Darmstaft Germany. More information and registration on our website.

Publication of the Month

The publication work of the month is:

S. Zuo, F. Lin and X. Wu, "Noise Analysis, Calculation, and Reduction of External Rotor Permanent-Magnet Synchronous Motor," in IEEE Transactions on Industrial Electronics, vol. 62, no. 10, pp. 6204-6212, Oct. 2015. doi: 10.1109/TIE.2015.2426135

In this paper the acoustic noise due to magnetic forces of an external rotor PMSM is studied experimentally and numerically using Ansys(R) software. The authors implement a noise mitigation strategy based on stator slot opening optimization. Unfortunately, the noise reduction obtained with calculation is not validated with experiments.

The vibroacoustic behaviour of outer rotor machines is very different compared to outer stator machines. In particular, any standing force waves in the stator reference frame becomes a rotating force wave in the rotor reference frame. This can result in additional sidebands in vibration and noise. MANATEE software can model external rotor topologies and noise mitigation strategies such as skewing, slot opening optimization, magnet shaping and current injection can be quickly implemented.

The noise troubleshooting tools provided in MANATEE are also applicable to outer rotor topologies.

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