Regenerative braking system development and perspectives for electric vehicles: An overview

Energy depletion and environmental pollution have always been challenges hindering the rapid development of the automotive industry. Electric vehicles (EVs), being promoted worldwide, are expected to bring benefits to energy security and environmental conservation. As one of the key technologies to improve energy efficiency and extend the driving range of EVs, regenerative braking has attracted extensive attention. The aim of this study is to review the configuration, control strategy, and energy-efficiency analysis of regenerative braking systems (RBSs). First, the configuration of RBSs is introduced, including the development of electric motors, friction braking actuators, and energy-storage units, and the application of RBSs to EVs is briefly elaborated. Then, the regenerative braking control strategy is summarized from three perspectives, that is, energy economy under general braking, braking stability under emergency braking, and driving comfort under braking mode switching. Among these, mainly the energy-recovery economy of the regenerative braking control strategy is analyzed. In addition, energy-transfer efficiency is analyzed considering the transmission system efficiency and low-speed working characteristics of electric motors. Finally, the challenges of RBSs in the application of EVs are discussed, which provides insights for future research.