MANATEE new features

MANATEE v1.05.03 has been released. It includes a new tutorial on Buried Permanent Magnet Synchronous Machines based on Prius 2004 case. MANATEE electromagnetic, structural and acoustic simulations are run in a few seconds and compare favourably with full FEA electromagnetic and structural calculations run in several hours. This tutorial can be fully tested with the MANATEE Demo version.

Outer rotor permanent magnet synchronous machines

MANATEE now includes the electromagnetic and vibroacoustic simulation of outer rotor permanent magnet synchronous machines. The electromagnetic subdomain models and the structural models have been extended for outer rotor structure.

Outer rotor permanent magnet synchronous machines simulation

Notches

The effect of notches can be modelled both in FEMM and permeance / mmf models. Notches can help reducing cogging torque and can also improve the vibration and noise levels due to magnetic forces. However notches can also potentially increase vibration level if not properly designed.

Effect of notches on the noise of an electrical machine

Subdomain model

The subdomain models have been further optimized to automatically account for periodicities and the calculation time is extremely low, even for topologies with high slot and pole numbers and low symmetries like concentrated winding PMSG for direct drive wind turbine applications.

Zoom on MANATEE feature

MANATEE can be particularly fast because the variable speed vibroacoustic calculations can be run from a single speed simulation using the "ideal sonagram" option, also called "synthesized spectrogram".
Based on a single speed simulation, MANATEE can identify the main force harmonics, their physical origin (magnet, armature field), and their rotational speed and directions: if the control of the machine allows to know the evolution of the currents as a function of speed (e.g. constant flux and constant power for a traction induction machine), the variable speed force spectrogram can be derived from this single speed simulation, and so for the whole acoustic noise and vibration behaviour. This assumption is easily fulfilled in the case of open-circuit permanent magnet machines where the magnitude of the Maxwell stress harmonics does not change with speed.

This feature is particularly useful as the maximum vibration and noise levels can be calculated in a few seconds with a very high number of speed steps, capturing the worst levels even with small structural damping.

The variable speed spectrograms can be obtained using the followings commands :

• plot_VS_Fr_spectrogram (radial force)
• plot_VS_Vr_spectrogram (radial velocity)
• plot_VS_Ar_spectrogram (radial acceleration)
• plot_VS_ASPL_sonagram (sound pressure level)
• plot_VS_ASWL_sonagram (sound power level)

Upcoming publications

EOMYS has finalized an article on the effect of current angle on the magnetic force harmonics in PMSM for the French conference SGE. Subdomain electromagnetic models which are run in a fraction of second give the same results as a reference article of M. Valavi from NTNU using FEA. It is shown that the current angle can have a significant impact on noise and vibrations and that a compromise may have to be done between torque maximization and noise and vibration minimization.

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