Torque Distribution-based Range Extension Control System for Longitudinal Motion of Electric Vehicles by LTI Modeling with Generalized Frequency Variable

Abstract

Electric vehicles (EVs) have been identified as alternatives to traditional engine vehicles because they have no tailpipe emissions and are cheaper to operate. However, limited mileage per charge partially prevents EVs from becoming popular. Although high-efficiency motors and large batteries can be employed to increase the cruising range per charge, pure control approaches for energy saving are more promising. To increase the cruising range of EVs equipped with front and rear in-wheel-motors, this paper proposes an optimal torque distribution algorithm for longitudinal motion by considering the transfer of weight between front and rear axles and motor losses. Then, by modeling an EV as a linear time-invariant (LTI) system with generalized frequency variables, a distributed control concept is proposed, in which part of the main controller's task is allocated to the local controllers. A stability criterion is established for the controller design, and the effectiveness of the proposed range extension control system is verified by both simulations and experiments.