Thermal modeling and drivetrain-loss study for thermal management of electric machines. Utilizing powertrain heat for better performance in cold conditions
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Mobility engineering (MPMOB), MSc
Publicerad
2023
Författare
Rosén, Filip
Tyrbo, Maja
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The number of battery electric vehicles, BEVs, are increasing as the transportation
sector is moving towards a more sustainable future with zero emissions. An issue
with BEVs compared to conventional vehicles is their shorter range. To achieve
higher efficiency and thereby longer range, every system on the vehicle must be optimised. This thesis has considered the thermal management system, cabin heating
in cold conditions, and the utilization of heat losses from the electric drive unit, EDU.
To understand the benefit of an EDU loss-mode, i.e. operating with higher losses
than nominal to create more heat, a thermal model of the electric machine was built.
The thermal model is a lumped-parameter model capable of predicting the temperature of critical components, which enables over-loading analysis to ensure that the
thermal capability of the machine is not exceeded. The model is parameterized only
by dimensions and material data, and can be easily customized to new motor types.
Verification with steady-state and WLTC test data showed good trend correlation
and within the expected accuracy of 30%.
A vehicle-level thermal management model was built to implement and utilize heat
losses from the electric drive unit. Simulations with an ambient temperature of
-10°C and heating the cabin to 20°C were performed with EDU heat losses. Simulations with motor preheating was also performed.
Reduction of energy consumption for cabin heating was found to be approximately
7% when utilizing drive unit heat losses. Motor preheating reduced cabin heating
consumption further, but used more energy over-all and was not found efficient.
Beskrivning
Ämne/nyckelord
thermal management , battery electric vehicle , lumped parameter thermal network , heat loss utilization , thermal simulation electric machines , electric machine thermal modeling