Optimal sizing and energy management of a novel dual-motor powertrain for electric vehicles

A novel dual-motor multimode coupling powertrain (DMMCP) is proposed for improving the energy efficiency of electric vehicles (EVs). The powertrain is based on a dual-motor with compound planetary device which provides two inputs for two motors to drive the vehicle. Specifically, DMMCP can achieve four driving modes which are two single-motor driving modes and two dual-motor driving modes. Firstly, the dynamic DMMCP model is established by the general characteristic equation of kinematics. Then, based on this dynamic model, optimization of DMMCP parameters and mode switching strategy are designed to obtain high efficiency. To achieve optimization of parameters, the improved particle swarm optimization algorithm (PSO) is employed. Also, based on instantaneous power optimal principle, the mode switching strategy is respectively devised for driving and regenerative braking conditions. To demonstrate the superiority of this proposed powertrain, a dual-motor torque coupling powertrain (ROEWE Marvel-X) is regarded as the reference powertrain. To maintain the accuracy of the economic comparison, the mode switching strategy of ROEWE Marvel-X is optimized by the same principle of DMMCP. Finally, the comparison results demonstrate that DMMCP can meet better economic performance.