October 2021 news: Next Manatee software webinar, e-NVH simulation on whole torque-speed plane, Slot modulation effects in EV/HEV applications, e-NVH simulation of electric drives

Manatee software news

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The registration to our next Manatee software free webinar planned for 3rd November is still open. Manatee is the only software specialized in the assessment and control of electromagnetic noise and vibration throughout the development lifecycle of electrical systems:

  • Powerful e-NVH postprocessing will be reviewed on BMW i3 EV electric motor.
  • Some fast and accurate calculation algorithms of Manatee V2 will be explained.
  • The modeling of uneven stator bore radius due to manufacturing tolerances will be demonstrated.
  • A case study on Audi e-tron induction machine acoustics due to electromagnetic forces will be presented.

Register to Manatee software presentation (Europe/Asia time zones)
3 Nov 2021, 09:00 - 10:00 CET
Register to Manatee software presentation (Europe/Americas EDT)
3 Nov 2021, 16:00 - 17:00 CET

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e-NVH simulation on whole torque-speed plane

In traction application, it can be useful to visualize the overall Sound Power Level (SWL) together with specific harmonics on the whole torque-speed plane. In the picture here below is an example showing acoustic noise maps of the Toyota Prius extracted with Manatee software.
Details to know how to set up the associated model with Manatee are given in a dedicated video accessible on our YouTube channel.

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Slot modulation effects in EV/HEV applications

Several scientific works such as [R1,R2] have demonstrated that pulsating vibrations (wavenumber r=0), which are particularly important in the vibro-acoustic behavior of EV/HEV traction motors, do not necessarily originate from pulsating Maxwell stress harmonics. Due to slot modulation effect, pulsating vibrations can also be produced by wavenumbers which are multiples of the slot number (e.g., r=48, r=96 etc. in a 48s8p PMSM). Electrical vehicles often use integer slot machine topologies such that open-circuit magnetic forces produce both radial and tangential pulsating forces at slot passing frequencies.
When facing a noise issue at the slot passing frequency, it is therefore tempting to redesign the magnetic circuit to damp r=0 Maxwell stress harmonic obtained from a 2D FFT of the airgap Maxwell stress. However, this approach is not correct as wavenumbers multiple of the stator slot passing frequency have a higher influence on pulsating forces observed by stator teeth.

In Manatee software, this slot modulation effect is correctly modelled so the problem of EV/HEV electromagnetic noise at slot passing frequency can be efficiently tackled.

[R1] S. Wang, J. Hong, Y. Sun and H. Cao, "Mechanical and Magnetic Pivot Roles of Tooth in Vibration of Electrical Machines," in IEEE Transactions on Energy Conversion, vol. 36, no. 1, pp. 139-148, March 2021, doi:10.1109/TEC.2020.3007802.
[R2] Wang, S.; Hong, J.; Sun, Y. & Cao, H. Analysis of Zeroth-Mode Slot Frequency Vibration of Integer Slot Permanent-Magnet Synchronous Motors IEEE Transactions on Industrial Electronics, IEEE, 2020, 67, 2954-2964

Conferences presentation supports

  • On October 14th, Martin Glesser, NVH R&D engineer at EOMYS, presented a paper entitled "Sound quality analysis of Electric Drive Units under different switching control strategies" at the last international SIA-CTTM Automotive NVH Comfort Congress, Le Mans (France).

The paper can be downloaded here.

  • On October 27th, Paul Gning, R&D electrical engineer at EOMYS held a presentation about "The impact of different modelling parameters such as B(H) curve model on the electromagnetic noise level of an electric vehicle traction motor at variable speed" at the UKMS seminar on Magnetic Technologies for Electric Vehicles, organized by the UK Magnetics Society.

The presentation can be accessed here

e-NVH measurement workshop

For French-speaking contacts, do not miss our first edition of a practical 1-day workshop focusing on measurements of electromagnetic noise and vibrations. The participants will be explained the main noise radiation causes of an electric motor due to magnetic forces by using dedicated measurements techniques and trainees are invited to bring their own measuring equipment if desired.

There are still some free places left. Please register on our training website or contact us by e-mail.

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