Evaluating, understanding,
and optimizing the propulsion
system with the Virtual Twin, a
simulation model that captures
the physical behavior of the
system, can significantly reduce
development time and costs.
everal aspects of propulsion system behavior can be
investigated with the Virtual Twin, but this article focuses
on e-drive durability and NVH.
In the e-motor – the key component of the e-drive – strong
electro-mechanical interaction between rotor and stator
results in dominant excitations, namely rotor and stator torque
and radial forces. The conventional approach, where these
excitations are pre-calculated for a few discrete operating points
assuming perfect sinusoidal current and without consideration
oJ tLe control system, is not sYƾcient Jor tLe :irtYal 8win.
Advanced Simulation with AVL EXCITE™ M
Our simulation solution AVL EXCITE™ M integrates an e-motor
control into the dynamic simulation model, which considers
the pulse width modulation of the inverter and thus uses real
e-motor currents. In addition, EXCITE M internally calculates
the motor excitation for any operating condition based on
pre-calculated motor characteristics. The advanced e-motor
approach in EXCITE M allows the investigation of the radial
offset and tilt of the e-motor rotor and takes the rotor skewing
into account.
Transmission Components and Bearing Dynamics
Besides the e-motor, the Virtual Twin model of the e-drive
includes transmission components such as shafts, gears,
Simulating E-Drive Transient
Driving Conditions with the
Virtual Twin
ding,
opulsion
al Twin, a
captures
of the
ntly reduce
costs.
bearings, and the housing. For the gears, EXCITE M provides a
detailed slice contact model that accurately captures the gear
dynamics that affect NVH. In terms of bearings, rolling element
contact to the bearing race is resolved, while the typical e-drive
JeatYre oJ ƽoating ring Fearings can Fe easily introdYced and
defined in )<'-8)ɸ1.
Transient Operating Conditions
% YniUYe asTect oJ edrives is tLat a significant Tortion oJ
their operating time is spent in transient conditions, where the
operating speed or load is changing. Therefore, understanding
the dynamics of transient operating conditions is key, especially
from the perspective of NVH and durability of the e-drive.
When operating under transient conditions, especially when
changing the torque direction of the e-motor, the gears and
Fearings will e\Terience imTacts, e.g., in tLe gear ƽanOs. 8Le
imTact level can Fe greatly inƽYenced Fy tLe settings oJ tLe
e-motor controller. EXCITE M, which resolves dynamics in the
time domain and incorporates advanced modeling capabilities
including control systems, is a unique and ideal solution
for investigating e-drives not only in stationary but also in
transient dynamic conditions.
Thus, the EXCITE M model can also be used as a Virtual Twin
for controller testing in real-world operating conditions.
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