Hybrid and electric vehicle (H/EV) technology is already well established in the automotive industry and a great majority of car manufacturers offer vehicles with alternative propulsion systems (hybrid or electric - H/E). This advancement, however, does not mean that all technical aspects of H/E propulsion systems have already been encapsulated or even fully understood. This statement is specifically valid for regenerative braking technology. In order to regenerate the maximum possible energy, which may be limited in real applications (e.g. by the charging ratio of the energy storage device(s)), the interaction of regenerative braking and the active driving safety systems (ADSSs) such as the anti-lock braking system (ABS) needs to be taken in to account. For maximum recaptured energy via electric motor (E-Motor) braking, the use of regenerative braking, which generates decelerations greater than 0.1g, should be deployed. This however, creates the possibility of ADSS intervention which limits the extensive use of regenerative braking for the full breath of the braking period.
In this paper, simulation results making use of a vehicle mathematical model are presented to highlight some important issues with regenerative braking control which are directly caused by the configuration of the driveline, namely one E-Motor fitted with an open differential. In the paper a regenerative braking controller based on slip control has been proposed to offer both a high level of restored energy and reduced braking distance, by maximizing on the traction for high deceleration braking maneuvers on a low mu surface.
