Sensitivity of Energy-Efficient Driving to Motor Efficiency for EVs

This paper is an extension of our previous study on optimizing energy-efficient speed profiles of electric vehicles. This paper investigates the influence of motor efficiency on performance, including the energy consumption and control modes through parametric studies, for a light weight military ground vehicle. A comprehensive comparison is conducted between the global optimal solutions obtained from DP with nonlinear motor efficiency, and the suboptimal solutions derived from various constant efficiencies. The global optimal solutions lead to about 2-3% lower energy consumption than the suboptimal solutions for the considered driving scenarios. It is observed that the energy consumption and control modes of the suboptimal solutions are hardly affected by the motor efficiency. For a flat road, the control modes of the global optimal solutions, characterized as Pulse and Glide, are considerably different from those of the suboptimal solutions. However, no significant difference is observed in control modes for a hilly terrain.