Efficiency Analysis of a Dual-Motor Electric Vehicle Powertrain

A novel dual-motor input powertrain with three-speed transmission (DM3ST) of electric vehicle (EV) is proposed in this paper; it has dual power inputs with a simple and compacted structure. It can operate in three gears and five driving modes by integrated control of the dual motors and the synchronizer position. In this paper parameters of gear ratios are selected according to vehicle dynamic requirements, driving modes are chosen by the optimization of the instantaneous efficiency, a dynamic model is established with MATLAB/Simulink to implement the optimal working mode, and two typical drive cycles which are New European Driving Cycle (NEDC) and the Highway Fuel Economy Test (HWFET) are tested. We choose a single motor with two-speed transmission (SM2ST) for comparison because it has the similar structure with DM3ST. The simulation results indicate that DM3ST can achieve economic performance of EV obviously. It also can decrease defect of power interruption and improve the driving comfort by torque control of two motors while shifting gears.