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@PHDTHESIS{Chen:1021037,
author = {Chen, Bicheng},
othercontributors = {Pischinger, Stefan and Andert, Jakob Lukas},
title = {{T}hermal behavior impact on electric motor sizing in
battery electric vehicles},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2025-09415},
pages = {1 Online-Ressource : Illustrationen},
year = {2025},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, Rheinisch-Westfälische Technische
Hochschule Aachen, 2025},
abstract = {The increasing popularity of electric vehicles (EVs) as
eco-friendly alternatives in the automotive industry has
been impeded by consumer apprehensions regarding limited
driving range. This work addresses this challenge by
focusing on two pivotal factors crucial for enhancing EV
efficiency and extending driving range: accurate temperature
monitoring and optimal sizing for electrical machines (EMs).
In response to the critical need for monitoring temperatures
in electric drivetrain components, a centralized compact
lumped parameter thermal network (LPTN) model is proposed.
Departing from conventional distributed thermal models for
each component, this thermal model considers the intricate
thermal coupling between the inverter, EM and gearbox.
Utilizing the measured and validated loss maps including the
detailed losses distribution in the permanent magnet
synchronous machine (PMSM), the model accurately calculates
component losses. A global linear parameter-varying (LPV)
identification approach is then applied to determine the
parameters of the LPTN model. Cross-validation with
independent experimental data of the US06 cycle on the
chassis dynamometer yields a maximum estimation error of
approximately 7 ◦C. Simulation results demonstrate the
effectiveness of the centralized thermal model in estimating
temperatures of critical parts while considering the thermal
coupling between components. Additionally, this work
introduces a promising approach known as "right-sizing" for
EMs. This involves an efficient scaling of thermal
parameters in a low-order LPTN model, enabling the
estimation of temperature for the scaled PMSM. The proposed
scaling approach facilitates a preliminary evaluation of the
thermal limits of the PMSM during the early stages of
development. Validation for both axial and radial scaling,
with scaling factors ranging from 0.8 to 1.2, is conducted
on a previously validated Ansys Motor-CAD model for typical
automotive driving cycles, revealing a maximum temperature
scaling error of less than 3.5 ◦C. The integration of the
LPTN model and the scaling approach into a whole vehicle
simulation model becomes instrumental in determining the
optimal size of a specific EM for diverse driving scenarios,
including urban and highway conditions. The pursuit of
optimization is guided by considering critical factors such
as the thermal constraints of the EM, the overall efficiency
and performance of the EV. Employing the ant colony
optimization (ACO) optimization algorithm results in the
identification of a Pareto front for urban and highway
scenarios. The optimization results suggest that a shorter
motor length is advantageous in both urban and highway cycle
scenarios. In urban scenarios, the optimized motor enhances
acceleration performance while lowering energy consumption.
However, in highway scenarios, there’s a trade-off between
energy consumption and acceleration, with the optimized
motor leading to a $2.84\%$ decrease in energy consumption.},
cin = {412310},
ddc = {620},
cid = {$I:(DE-82)412310_20140620$},
pnm = {CEVOLVER - Connected Electric Vehicle Optimized for Life,
Value, Efficiency and Range (824295)},
pid = {G:(EU-Grant)824295},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2025-09415},
url = {https://publications.rwth-aachen.de/record/1021037},
}