Seamless mode shift control for a new Simpson planetary gearset based dual motor powertrain in electric vehicles

Abstract

This paper proposes a seamless mode shift control strategy for a Simpson planetary gearset based dual motor powertrain (SPGDMP) which has 6 driving modes. The dynamic model of SPGDMP is built, where the rotational inertia of transmission components, the flexibility of shafts, dynamic response of motor torque and brake pressure, and stick-slipping friction phenomenon of brake are considered. A seamless mode shift control strategy is proposed to avoid power interruption and reduce the vehicle jerk. The mode shift is decoupled to the torque transition process and speed transition process, which lowers the control difficulty. The step function is used to produce the smooth transition trajectories of torque and speed, which eliminates the large vehicle jerk induced by the unsmooth driving torque. In the speed transition process, a combination of speed feedback and torque feedforward control strategy is proposed to track the designed motor speed trajectory and the driver's input torque simultaneously. The simulation results demonstrate that the proposed mode shift control strategy can reduce the peak-to-peak value of vehicle jerk to a value below 2 m/s3.