MANATEE software for the NVH simulation of electric powertrains

© 2013-2018 EOMYS ENGINEERING / 121 rue de Chanzy CS10128 59030 Lille Cedex FRANCE / www.eomys.com / contact@eomys.com
MANATEE® SIMULATION SOFTWARE
Magnetic Acoustic Noise Analysis Tool for Electrical Engineering

I. OVERVIEW OF MANATEE FOR E-NVH
MANATEE is the central point for the integrated Noise, Vibration, Harshness design process of electric
powertrains (e-NVH), from basic vibro-acoustic design at e-motor level to detailed vibro-acoustic design at
system level:
2
Third-party sound quality /
psychoacoustics tools
Third-party electromagnetic
design tools
Third-party structural
design tools
Third-party acoustic
design tools
Third-party gearbox NVH
design tools
Standalone e-motor
NVH solution
©Masta
©Actran
©HeadAcoustics
©Jmag
©Ansys
Third-party NVH data
acquisition tools
©Oros

MANATEE v1.07. graphical environment:
Scripting environment
(Matlab)
Command line
post-processings
(Matlab)
GUI for machine &
simulation set-up
(Python)

MANATEE built-in fast electromagnetic models are based geometrical templates (cf. website).
New lamination shapes can be easily implemented by EOMYS upon request:
The following radial flux electrical machine topologies are included in MANATEE v1.07:
• Inner rotor squirrel cage induction machine, doubly-fed induction machines
• Inner or outer rotor surface, inset or buried permanent magnet synchronous machine
• Wound rotor synchronous machines

A few figures about MANATEE:
• Up 40 dB acoustic noise reduction after redesign based on EOMYS consulting activities
• Successfully applied on more than 50 industrial cases with IPMSM, SCIM, WRSM, DFIG, inner & outer rotor,
from W to MW range, from 5 rpm to 150 000 rpm, from 10mm to 10m diameter machines
• more than 120 validation simulation projects
• more than 120 graphical post-processings
• ~60000 code lines (without counting comments)
Naval

7
Magnet /
current
excitations
ELECTROMAGNETIC
MODULE
ELECTRICAL
MODULE
STRUCTURAL
MODULE
ACOUSTIC
MODULE
MANATEE software seamlessly integrates the following multiphysic modules:
Dynamic
vibrations
Variable
speed NVH
Geometry
and control
parameters
3D force
distribution
THERMAL MODULE
VARIABLE SPEED MODULE
MULTI-SIMULATION MODULE
OPTIMIZATION MODULE
The interface between physics (e.g. mesh to mesh projections) are automatically defined.
All module inputs can be user-defined / imported if necessary, resulting in a flexible simulation workflow.
Module interface is documented for possible integration in third-party scripts.

II. E-NVH ELECTRICAL MODEL OPTIONS
EQUIVALENT CIRCUIT
Option 1: Simulink® PWM block
Option 2: Analytical / numerical PWM
Phase voltage
waveforms
PWM MODEL
User-defined voltage
waveforms
Phase current
waveforms
User-defined current
waveforms
• PWM model with several strategies (synchronous, asynchronous, calculated, full wave) including
randomized switching strategies
• No strong circuit (yet) in v1.07
Machine and
converter input
parameters
User-defined
equivalent circuit

9
MANATEE electromagnetic model relies on the fast calculation of the airgap radial and
tangential flux density with the combination of the following modelling methods :
• Permeance / magnetomotive force analytical models (PMMF)
• Subdomain semi-analytical models (SDM)
• Finite element non-linear magnetostatic model (FEMM)
Import of airgap flux from third-party electromagnetic software is supported.
III. E-NVH ELECTROMAGNETIC MODEL OPTIONS

Option 1: 2,5D ANALYTICAL PERMEANCE / MMF MODEL User-defined airgap
flux distribution
Phase current
waveforms
Option 2: 2,5D SEMI-ANALYTICAL SUBDOMAIN MODEL
Option 3: 2,5D FINITE ELEMENT MODEL (FEMM)
Analytical mmf in linear case using
winding function model
Analytical permeance incl.
geometrical assymetries (e.g.
uneven airgap, eccentricities)
FEA permeance incl. saturation,
magnetic wedges, notches…
Airgap time and
space flux
distribution
FEA mmf including non linearities

Permeance/ MMF Subdomain FEMM
Calculation time Very fast Fast Slow
Tangential field calculation No Yes Yes
Torque ripple calculation No* Yes Yes
PWM currents Yes Yes Yes
Robustness to geometry Limited Limited Good
Skewing (multislice) Yes Yes Yes
Saturation Limited (saturated
permeance waves)
No (except on
IPMSM rotor**)
Yes
Eccentricities Yes No Yes
Uneven airgap Yes No No
Pole displacement, demagnetization Yes Yes Yes
Stator short-circuit Yes No* No*
IM broken bar Yes Yes No*
Topologies IPMSM**
SPMSM
SCIM
DFIM
WRSM
IPMSM**
SPMSM
SCIM
DFIM
WRSM
IPMSM
SPMSM
SCIM (no-load)
DFIM
WRSM
*can be modelled but not included yet in MANATEE v1.07
**fast hybridation with FEMM
Subdomain model on SPMSM:
Permeance/mmf model on SCIM:

12
Model hybridation is possible in MANATEE such as
• Calculation of mmf using non-linear FEMM (e.g. rotor mmf for interior magnet machines)
• Calculation of permeance using non-linear FEMM (e.g. saturation effects, notch effects,
magnetic wedges)
Recommended fast electromagnetic models in symmetrical healthy case:
Permeance/mmf
SCIM SPMSM, IPMSM, WRSM
Subdomain

• Any winding type can be modelled (integral, fractional, user-defined, multiphase)
• A winding pattern defined in Domolites (formerly Koil) freeware can also be imported

• High accuracy and fast subdomain model for synchronous machine:
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• Automatic coupling with FEMM finite element software (symmetries, boundary conditions) in order
to model more complex problems (e.g. shaped magnets, saturation effects)
Finite element
magnetostatics (FEMM)
5 min
MANATEE subdomain models
0.1 s
space
timetime
space

> 1 hour of calculation 1 sec of calculation
• Comparison between Altair Flux® (FEA) and MANATEE ® (SDM) airgap flux distribution in time and
space on a loaded SPMSM include non-linearity:

IV. E-NVH MAGNETIC FORCE CALCULATION OPTIONS
Stator and rotor nodal or lumped
Maxwell harmonic forces and moments
Airgap time and space
flux distribution
MAGNETIC FORCE CALCULATION,
PROJECTION AND 2D FFT
• Lumped force load vector
• Surface distributed nodal forces
• Virtual Work Principle nodal forces
Torque ripple
r=0 r=2 r=3
• Torque ripple and cogging torque are naturally obtained as a particular case of magnetic forces
• Trade-offs between torque ripple and noise minimization can therefore be obtained with MANATEE

S=Enveloppe fermée
Dynamic radial
deflections
Option 1: 2,5D ANALYTICAL CYLINDER MODEL
Static radial deflections incl.
tooth-induced moments
Natural frequencies of the circumferential
modes of an equivalent ring
User defined natural frequencies
(e.g. experimental data)
Natural frequencies
automatically calculated by
FEM (GetDP) on a 3D model
FRF calculation of main force
wavenumbers
Dynamic radial deflections
Vibration synthesis of radial
deflections
Option2: 3D FINITE ELEMENT STRUCTURAL MODEL
Optistruct/Ansys (commercial) or GetDP (free)
Harmonic
magnetic forces
V. E-NVH STRUCTURAL MODEL OPTIONS
BASIC DESIGN
DETAILED DESIGN

Tangential and radial harmonic
magnetic forces (magnitude,
wavenumber, frequency, phase)
3D airgap flux
distribution
HARMONIC FORCE
PROJECTION
r=2 r=3
ELECTROMAGNETIC
MODEL
r=0
STRUCTURAL MODEL
Unit rotating loads
of wavenumbers
r=0, ±2, ±4 …
STRUCTURAL FREQUENCY
RESPONSE FUNCTIONS
r=0 r=2
ELECTROMAGNETIC
VIBRATION SYNTHESIS
Complex FRFs (radial &
tangential) for each
wavenumber r
Vibration and noise spectrograms
Operational Deflection Shapes
Modal contribution
Radiating surface velocities
Electromagnetic Vibration Synthesis (EVS): faster than a direct coupling, with more physical insights
• 2D or 3D external FEA software (Flux,
Jmag, Maxwell, Magnet etc…)
• Manatee 2,5D analytic model
• Manatee 2,5D semi analytic model
• Manatee 2,5D numerical model (FEMM)
• 3D external FEA software (Optistruct,
Ansys, Actran)
• Manatee 2,5D analytic model
• Manatee numerical model (GetDP)
Torque/speed curve
(variable speed
control law)
SPECTROGRAM
SYNTHESIS

Coupling with third party structural FEA :
• Possibility to automatically call from MANATEE an existing FEA model of Optistruct /
Ansys / GetDP, or to rebuild a lamination model (« concept stator ») from scratch:
• circular lamination with any slot geometry (possibility to simplify the slot geometry to
have a lighter structural model)
• application of physics: orthotropic properties, winding mass
• application of boundary conditions (e.g. clamped/clamped, free/clamped, fixed nodes)
• meshing based on the number of nodes in the different regions
• Automated magnetic force application (load collectors)
• Vibration synthesis post-processing using operational magnetic loads from MANATEE
electromagnetic model or third party electromagnetic software

Coupling with open-source structural FEA GetDP:
• Automated mesh generation using Gmsh
• Automated identification of coupled circumferential / longitudinal modes
with different boundary conditions
• Modal shape selector to visualize the modes and validate the automated
modal identification
(2,0)
(3,0)
(4,0)
(0,0)
(2,1)
(3,1)
(4,1)

CLAMPED – FREE
Boundary conditions
FREE – FREE
Boundary conditions
Resulting modal basis (simplified representation of cylindrical modes – « tooth rocking modes » are included):

22
Dynamic radial
deflections
SEMI-ANALYTICAL ACOUSTIC MODEL
Radiation efficiency of an equivalent cylinder
VI. E-NVH ACOUSTIC MODEL OPTIONS
Sound power level
Sound pressure level
2D (analytical) or 3D (FEM) spatial-averaged
vibration velocity
Sound synthesis .wav

Spectrogram Synthesis algorithm: fast calculation of variable speed NVH behaviour
Single speed calculation
Extrapolation at higher speeds
Extrapolation at lower speeds
• Calculation of electromagnetic excitations at only 1 to 6 single speeds depending on load state
• Extrapolation of operational magnetic loads to variable speed based on the knowledge of the
evolution of magnetic forces with operating point and Id/Iq strategy
• Speeds-up NVH calculation and reduces parasitic forces as there is no need to interpolate magnetic
force harmonics magnitude between speed

VII. KEY FEATURES OF MANATEE SOFTWARE
• Fast variable speed vibroacoustic calculation (from 1 sec to 1 mn) based on efficient
calculation methods even with 3D effects and converter harmonics
• Possibility of decoupling electromagnetics & structural mechanics (EVS algorithm) to speed
up NVH Vs electromagnetic performances optimization studies
• High frequency acoustic calculations (up to 20 kHz) within seconds, contrary to numerical
approaches
• Large number of NVH root cause analysis post processing tools
• Easy implementation of all e-machine noise and vibration control actions (e.g. current
injection, skewing, pole shaping, notching)
• Extensive online documentation with tutorials and validation cases
24

VIII. VALIDATIONS AND DOCUMENTATION
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• A full website is dedicated to MANATEE validations, post-processings, and tutorials:
www.manatee-software.com
• All modules are validated using special validation projects which can be run and modified by the
user:
>>run_MANATEE(‘EM_SPMSM_NL_001');
• Validation cases are daily tested on the current version of MANATEE
• The input and output simulation data are stored in structures and substructures which are
documented in an Excel file
• Three main tutorials for the electromagnetic and vibroacoustic simulation of squirrel cage
induction machines, interior and surface PMSM

EXAMPLES OF MANATEE SOFTWARE VIBRO-ACOUSTIC VALIDATIONS
Case of a traction concentrated winding PMSM with interior magnets at partial load (blind test):
Sound level during a run-up
(experiments with gearbox+water-
cooling+converter harmonics)
(MANATEE simulation without
converter harmonics)
~10 sec on a laptop
TESTS MANATEE
Motor A
Motor B
-40 dB
Fast electromagnetic model neglecting saturation can be used in basic design phase to avoid
strong resonances, no need of detailed multiphysic numerical models

Case of a squirrel cage induction motor of a naval dredge pump at no-load:
(experiments with PWM +
gearbox +air-cooling)
(simulation without PWM)
~2 sec on a laptop
15 dB reduction reached after redesign with MANATEE (change of rotor slot number)
TESTS
MANATEE
gearbox lines

Case of a railway squirrel cage traction induction machine with Sound Power Level measurements according
ISO3745 in semi-anechoic chamber:
Sound power level during run-
up (including fan noise)
Sound power level during a run-up
(without air cooling)
~2 sec on a laptop
TESTS
MANATEE
Fast vibroacoustic model neglecting 3D effects can be used in basic design phase to avoid

Case of a salient pole synchronous hydroelectric generator with damper bars
~10 sec on a laptop
TESTS MANATEE
2 resonances

Case of a traction distributed winding PMSM with interior magnets at partial load:
(experiments in non ideal acoustic
conditions)
(MANATEE, coupling with non linear FEMM)
~6 hours on a standard PC
(MANATEE simulation, linear subdomain)
~10 sec on a standard PC
overall
SPL avg 3
micros

Geometry / Currents
(manual, automated import
upon request)
IX. MANATEE INTEGRATION TO YOUR DESIGN WORKFLOW
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Step 1 : basic electromagnetic + basic vibro-acoustic design loops
Option A. Standalone electromagnetic &
vibroacoustic design optimization
Option B. Coupling with third partly fast
electromagnetic design tools (optional)
Speed, FluxMotor, RPMXpert etc.
• Fast assessment of electrical machines air-borne noise to rank different topologies (ex: SyRM Vs
IPMSM, slot/pole combinations) at variable speed along torque/speed curve under sine supply
• Possibility to drive MANATEE models from Python/Matlab scripts
• First electromagnetic design NVH optimization by implementing electrical noise mitigation
techniques (skewing, notching)
Matlab/Python scripts
Note: these workflows are given as examples, other use may be possible

32
Step 2 : detailed electromagnetic + basic vibro-acoustic design loops:
Coupling with third party FEA
electromagnetic design tools
Airgap flux
lookup tables
NVH maps in torque/speed plane
Skew / torque ripple / axial ripple optimization
• Refinement of electromagnetic force calculation (e.g. 3D model with axial effects, strong circuit
coupling, more complex lamination magnetic circuit)
• Fast study of best trade-offs between NVH, torque ripple, losses etc on the whole operating
range using MANATEE flux interpolation, skew optimization, noise maps, sensitivity study features

MANATEE simulation software can be used for the electromagnetic design optimization of electrical
machines including the analysis of magnetic vibrations and acoustic noise due to Maxwell forces.
MANATEE unique features include:
• - quick NVH calculation during early electromagnetic design loops
- optimized NVH calculation in detailed design phase (coupling with structural FEA) over full
operating range
- advanced post-processing for NVH root cause analysis
- design optimization environments of e-motor noise mitigation techniques
MANATEE is currently under Matlab® (R2009b or later), but its Graphical User Interface is in
Python/Qt to set-up the machine and simulation parameters.
MANATEE does not use any Matlab toolbox.
3

MotorCAD
Other import / export options
• MANATEE can import magnetic forces calculated by MotorCAD
• Magnetic forces calculated by MANATEE on rotor & stator can be
exported to Romax/AVL Excite/LMS Virtual.Lab (.unv)
Vibration and
noise
Vibration
Magnetic
forces
Magnetic
forces

X. POST PROCESSINGS & PLOT TOOLS
35
• MANATEE includes more than 120 plot commands directly accessible in command line
• Example of Matlab
quick plot command
without arguments

36
Geometry, time and space visualization, real and complex spectra for all quantities (permeance, mmf,
radial and tangential flux density, force, acceleration, velocity, displacements), 2d/3d animation

37
Magnetic harmonic forces analysis with automated identification of lines expression
(PMSM) (SCIM)
Wavenumber

38
Magnetic harmonic forces analysis

39
Automated analysis of magnetic force waves in open circuit / partial load
>> find_harmonic_PMSM_open_circuit(2, 10, 5, 12)
Force wave {f=10fs, r=2} is created by the product of flux waves B1=P1.F1 and
B2=P2.F2 such as:
B1={0,0}.{9fs,9p} and B2={0,-4Zs}.{fs,p}
B1={0,0}.{fs,p} and B2={0,-4Zs}.{11fs,11p}
B1={0,0}.{7fs,7p} and B2={0,-4Zs}.{3fs,3p}
B1={0,0}.{5fs,5p} and B2={0,-4Zs}.{5fs,5p}
B1={0,0}.{3fs,3p} and B2={0,-4Zs}.{13fs,13p}
B1={0,0}.{5fs,5p} and B2={0,-4Zs}.{15fs,15p}
Example of a 12s10p PMSM (Zs=12, p=5) in open circuit conditions: to know how the origin of the force
wavenumber r=2 occurring at f=10fs one can simply type:
stator slotting
permeance waves
rotor magnet
flux density waves

Static (top) and dynamic (bottom) radial vibration spectra
Possibility to plot frequencies as electrical
or mechanical orders

Spectrogram of radial / tangential force harmonics for each spatial wavenumber

Spectrogram of radial / tangential force harmonics of a given order, including rotation direction
Operational deflection shapes at a given frequency

Plot of tangential and radial forces per tooth in time and frequency domain
r=0 r=2 r=3

Space vector diagram to analyze the origin of a radial or tangential flux density in terms of
permeance and magnetomotive force waves

Possibility to visualize the modal basis under Gmsh (freeware)

47
Modal contribution to acoustic and vibration spectra up to 20000 Hz

Contribution of each structural mode to the acoustic noise at variable speed

Spectrogram and order analysis with automatic identification of main magnetic force
harmonics orders and frequencies

« Spatiogram » noise analysis: decomposition of acoustic noise spectrogram per force wavenumber
=
r=0
r=2
+ +…
r=4
+

Order analysis per circumferential vibration wavenumber (including rotation direction)
r=0 r=1
r=+2r=-2

Acoustic noise maps in torque/speed plane
First resonance depends on torque/current level
-> due to armature/pole/slot interactions
Second resonance independent of torque/current level
-> due to pole/slot interactions (open circuit noise)
Example of a 48s8p IPMSM with stepped-skew rotor
NVH behaviour is different in traction and braking

Automated skew optimization environment
• Automated study of torque maximization / torque ripple minimization / noise minimization tradeoffs
• Fast calculation based on flux lookup table as a function of Id/Iq
• Possibility to use this tool based on FEMM or third party FEA electromagnetic software

Automated harmonic analysis
• Automated study of e-motor NVH harmonic sources
• Rotor/stator winding space harmonics, rotor/stator slotting, PWM, saturation, eccentricities

Unbalanced magnetic pull calculation (example of the slotting effect on eccentric UMP
including skew of the stator)

Listen to your electrical machine (direct sound synthesis)
• Sound synthesis can be carried at single speed or variable speed
Sound with 4800 Hz PWM Sound with 10000 Hz PWMSound under sine supply
Run-up at variable speed
• Sound can be exported to third party sound quality software (e.g. LEA from Genesis, Artemis from
HeadAcoustics) to include other sources of noise (e.g. aerodynamic, mechanic) and to calculate
psychoacoustic metrics

is_mmfs
is_ideal_mmfs
is_mmfr
is_ideal_mmfr
is_slotS
is_slotR
LwrA
LwrA_max
ism
mfs
dealm
mfs
ism
mfr
dealm
mfr
iss
lotS
iss
lotR
LwrA
LwrAm
ax
corr factor
0
0.2
0.4
0.6
0.8
1
Automated harmonic source analysis on electromagnetically-excited noise
High correlation between maximum noise level
and rotor slotting harmonics
High correlation between maximum noise level and
rotor mmf
Low correlation between maximum noise level and
stator winding armature spatial harmonics
High correlation between maximum noise level
and nominal noise level

5D « Muti-simulation Viewer » for post processing sensitivity & optimization results

XI. CONCLUSIONS
• MANATEE is the only software fully dedicated to the assessment of magnetic forces, magnetic vibrations
and acoustic noise with validated force projection algorithms and validated noise results
• MANATEE is the only simulation environment giving physical insights on e-NVH, combining noise
troubleshooting and noise mitigation tools
• MANATEE can be integrated both in pre-sizing and detailed design workflows and provides accelerated
simulation times compared to a direct coupling approach
• MANATEE semi-analytic models and numerical algorithms give no parasitic numerical noise
• MANATEE is highly flexible based on Matlab/Python scripting
• MANATEE can be used as a standalone electromagnetic design software of electrical machines
60
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MANATEE software for the NVH simulation of electric powertrains

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