Range extension control system for electric vehicles by LTI modeling with generalized frequency variable

Electric vehicles (EVs) have been identified as being alternatives to traditional engine vehicles due to their reduced impact on environments. However, as one of the inherent disadvantages, limited operating range prevents EVs from wide spreading. Although high efficiency motors and large-size batteries can be employed to increase mileage per charge, pure control approaches for cruising range extension are more interesting and promising. For EVs equipped with front and rear in-wheel-motors, the cruising range can be extended by optimal torque distribution among all the wheels. On the other hand, an increasing number of control functions are desired for EVs. For example, control systems for safety, comfort and economy have been developed and utilized in the recent decades. Nevertheless, too many control functions exert heavy processing burden on the onboard control unit. In this paper, by modeling an EV as a LTI system with generalized frequency variables, a new control concept is proposed to extend cruising range, in which the process task is distributed to subsystems and the burden of the central controller can be released. Moreover, the stability criteria are established for the controller design, and the proposed range extension control system is verified by simulation.