May 2019 Newsletter: e-NVH workshops, MANATEE coupling with Actran/Nastran, Pyleecan project

e-NVH workshop at SAE NVH conference

EOMYS organizes at the SAE Noise, Vibration, Harshness conference held in Grand Rapids, MI, USA, a free technical workshop on NVH due to electromagnetic forces in electric motors used in EV/HEV powertrains the 11th June 2019 at 6:30 PM after the networking session.

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e-NVH training at EOMYS office

EOMYS organizes a 4 days technical training on electromagnetic noise and vibrations in electrical machichines in its office in Lille, France (north of France - 1 hour from Paris) from 11 to 14 Sept 2019.
Registration can be accessed on our technical training webpage. The optional last day focuses on the use of MANATEE simulation software for the design of low noise electrical machines.

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MANATEE coupling with Actran/Nastran

MANATEE software for the vibroacoustic simulation of electric motors has been recently coupled to Actran/Nastran solvers from MSC software. This means that the fast vibroacoustic model of MANATEE based on a cylindrical shell modelling of the stator can be replaced by a more accurate finite element model when necessary (e.g. complex acoustic environment or complex geometry). The Electromagnetic Vibration Synthesis algorithm is still available to optimally couple MANATEE calculation of magnetic excitations with the NVH model.

Comparison of MANATEE semi-analytic vibroaoustic model with FEA from ACTRAN
Comparison of MANATEE semi-analytic vibroaoustic model with FEA from ACTRAN

This validation case compares a concept stator submitted to a rotating magnetic force of wavenumber r=2 at variable frequency using:

  • MANATEE built-in fast vibroacoustic model based on an equivalent cylindrical shell,
  • Nastran to compute the vibration, then using Actran to compute the acoustic field.

One can see that both simulation methodologies give similar results on a concept stator case. The 2.4 dB difference between FEA and semi analytic model is due to difference in radiation efficiency at resonance which occurs near cut-off frequency of the stator elliptical mode, it is therefore illustrating a worse case on a concept stator case.

When semi-analytical assumptions are valid, MANATEE provides global sound power level indicator within a much shorter time compared to FEA approach. Still coupling MANATEE with Actran/Nastran is required for more complex acoustic environment or assembly geometry modelling.

Ongoing MANATEE developments

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MANATEE version v1.08.01 has been released, with important features such as

  • handling of SynRM & SRM topologies,
  • FEMM calculation speed-up with VWP and better mesh management,
  • improvement of simulation script readability.

The team is currently working on the following features:

  • new spectrogram display suitable for fast PWM spectrogram synthesis feature,
  • visualization of FRF deflection shape,
  • implementation of DPWM switching strategies: GDPWM, DPWMmin, DPWMmax etc,
  • implementation of non-salient pole synchronous generators with unevenly distributed slots.

PYLEECAN project

The website of PYLEECAN open-source project for the electromagnetic simulation of electrical machines under Python is now online. The project includes full coupling with FEMM (symmetries + sliding mesh), and validation projects on key topologies such as IPMSM, SCIM, SPMSM.

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The code of PYLEECAN is available on Github. If you want to contribute to PYLEECAN you can either send an email to or contact us in the issue pages of Github. We are looking in particular for contributors for the electrical module.

Conferences and Events

EOMYS is about to organize or participate to the following events related to e-NVH:

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