Methods and applications of energy saving control of in-wheel motor drive system in electric vehicles: A comprehensive review

Energy saving techniques have been widely employed for traditional centralized motor drive electric vehicles (EVs) to improve the efficiency and driving range. Wheel motor drives, including in-wheel motor installed inside the wheel hub and near-wheel motor installed very close to the wheel hub can be controlled independently and accurately to provide drive and regenerative braking torque. Recently, wheel motor drive (WMD) electric vehicles (EVs) have been developing rapidly. However, only a few researchers have conducted a comprehensive survey on energy saving control methods and applications for WMD EVs. This paper presents a comprehensive review of energy saving methods and applications for EVs, as common approaches in energy saving and regenerative braking are reviewed. Then, regenerative braking in EV is presented in detail, including control strategies, simulation methods, energy storage system, case study, and efficiency and optimization methods. Moreover, the motor efficiency and motor loss efficiency optimization are discussed. Finally, the future research trends in energy efficiency saving control methods for EVs are elaborated. Therefore, this review not only provides a comprehensive analysis of recent energy saving control methods and applications for EVs but also demonstrates insights into new directions and optimizations for energy saving technologies for environmentally friendly and traffic-friendly EVs in a smart city.