Integrated design optimization of the transmission system and vehicle control for electric vehicles

摘要

The focus is on the combined design optimization of the transmission design and control design for an electric vehicle. In literature, these design problems are treated separately, whereas combining both mathematically coupled design problems into an integrated problem improves optimality. A shiftable transmission, e.g., a continuously variable transmission (CVT), allowing a smooth and continuous transition between the powertrain operation points further optimizes the energy usage, yet also allows further the reduction of the electric machine (Nm/W) and transmission specifications (overall speed ratio) in comparison with an optimized fixed-gear transmission. Moreover, a CVT enables for autonomous driving electric vehicles to further increase the driving range without compromising the vehicle performance. The influence of the transmission type, losses and driving conditions (average speed) are investigated for an EV of which the travelled distance, velocity and speed ratio (for the CVT) are the controlled states.