EOMYS develops MANATEE the only numerical simulation software specialized in e NVH design optimization

1. © 2020 EOMYS ENGINEERING – www.eomys.com
EOMYS ENGINEERING
e-NVH experience in EV/HEV applications
05/05/20
Jean Le Besnerais
1

2. © 2020 EOMYS ENGINEERING – www.eomys.com 2
Introduction
• EOMYS ENGINEERING was created in 2013 and has more than 80 customers worldwide, mainly in
automotive domain in the last 2 years
• EOMYS analyzed more than 100 e-motor electromagnetic noise and vibration issues, reaching up to
40 dB reduction after redesign
• EOMYS unique experience covers all e-motor topologies (axial/radial flux, inner/outer rotor,
induction/synchronous motors, concentrated/distributed winding, rotor/stator skew, IPMSM,
SPMSM, SCIM, SRM, SyRM, …)

3. © 2020 EOMYS ENGINEERING – www.eomys.com 3
Introduction
• EOMYS develops MANATEE the only numerical simulation software specialized in e-NVH design
optimization
• EOMYS has its own e-NVH testing equipment to provide advanced testing services, and partners
with OROS to develop dedicated EV/HEV acquisition system solutions
• EOMYS has delivered face to face technical trainings to more than 150 engineers on e-NVH
• EOMYS can therefore work at design stage or after manufacturing, including know-how transfer

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Why working on e-NVH?
• Topology and slot/pole combination can have +/- 20 dB impact on NVH due to magnetic forces
• E-motor designers have to work on electromagnetics, heat transfer… and vibro-acoustics
• e-NVH excitations and transfer paths are complex (rotor/stator, radial/tangential/axial, air-
borne/structure-borne, resonance/forced conditions, slotting/switching, sound quality)
• Most efficient e-NVH techniques lead to electromagnetic performance reduction so trade-offs must
be made (e.g. skewing reduces efficiency)

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Main EV / HEV traction motor projects
E-NVH project n° 47 61 74 78 82 84 86 92 96 103 107 108
109,
111,
113
11
2
116,
117,
118,
119,
120,
122
123,
127,
128
129,
133,
134
126 141 144
Concept design analysis * * * * * * * * *
E-NVH assessment in early design
stage (2.5D em + sm)
* * * * * * * * * * * * * * *
E-NVH assessment in detailed
design stage (3D em + sm)
* * * * * * * * *
E-NVH issue troubleshooting based
on simulation
* * * * * * * * * * * * * * *
Application of noise mitigation
techniques based on simulation
* * * * * * * * * * *
Design of NVH test campaign * * * * * * * * * *
Run of NVH tests * * *
Post processing of e-NVH test data * * * * * * * * * * * *
Sound quality analysis *
E-NVH issue troubleshooting based
on test data
* * * * * * * * * * * * * *
Validation of noise reduction based
on tests
* * * * * * *
Simulation know-how transfer * * * * * *
Testing know-how transfer * * * * *
Prototype level * * * * * * * * * * *
Series production level * * * * * * * * *
Machine position P2 P3 P3 P3 P5 P0? P3 P2 P0? P3 P2 P2/P3 P2/P3 P0 P2 P2 P2 P2 P5 P2 P2/P
3?

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Main references in EV/HEV applications

7. © 2020 EOMYS ENGINEERING – www.eomys.com 7
Examples of EV / HEV traction motor projects
Background & requirements
• Customer observed a high noise level on its e-powertrain during type tests
• Sound level was over requirement of 95 dBA at 1m
• Nominal torque reduction should be below 3% during redesign
Achievements
• Noise reduction of 40 dB
Activities
• Analysis of available test data to confirm its magnetic origin and
identify the most probable cause of noise
• Build-up of a 2,5D magnetic, structural & acoustic model under
MANATEE
• Confirmation of test data interpretation based on simulations
• Proposal of e-NVH mitigation techniques based on structural or
magnetic modifications
• Set up and run of a constrained multi-objective design optimization
problem after discussions with Customer
• Choice of a final solution in design space of a given electromagnetic
and NVH performance trade-off
• Follow-up of prototyping and validation tests

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Examples of EV / HEV traction motor projects
Background & requirements
• Design was rejected by end-customer due to large H40 levels
Achievements
• Understanding of electromagnetic excitation origin
• Proposal of alternative designs to reduce H40 tonality
Activities
• Analysis of available test and simulation data
• Advisement of additional tests to be run by Customer
• Theoretical analysis of magnetic forces to elaborate e-NVH
transfer path scenario
• Development and validation of a full 3D magnetic, structural &
acoustic model under MANATEE
• Confirmation of the root cause of noise
• Parameter sweep to reduce H40 tonality

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Automotive industrial clusters, R&D and testing facilities
• EOMYS ENGINEERING is part of several French industrial clusters working in automotive sector
• EOMYS ENGINEERING hosts several PhD students on magnetic noise and vibration reduction
applicable to automotive domain, collaborating with L2EP & LSEE laboratories
• EOMYS ENGINEERING has access to a e-powertrain semi anechoic testing facilities (CrittM2A, LSEE)

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Conclusions
• EOMYS is the most reliable partner for EV/HEV e-NVH studies at design stage or after manufacturing,
from simulation to testing