Modelling and optimisation of pure electric vehicle powertrains: a comparison of single and two speed transmissions

摘要

The purpose of this paper is to investigate the integrated design and selection of transmission and electric machine for the development of multi-speed electric vehicle (EV) powertrains. Multi-variable optimisation, in the form of genetic algorithms, is applied to the systems design of single and two speed EVs powertrains. Simulation-in-the-loop-based optimisation for the determination of primary motor, transmission and driveline design variables is conducted through the application of alternative driving cycle scenarios. The results for two speed optimisation demonstrate the capability to meet vehicle performance demands at a reduced motor size without increasing losses in the motor. Whilst, comparison of result for both single and two speed powertrains has demonstrated that the two speed provides a more consistent average cycle loss across alternative driving cycles, and improved low speed acceleration. Additionally, the impact of driving cycle selection is demonstrated to strongly influence outcomes of the optimisation procedure.