Torque distribution method based on vibration instability of PS-HEV transmission system

Abstract

The power-split hybrid electric vehicle has multiple working modes, which can be switched to different working mode according to different working conditions. The main switching process involved in the vehicle driving is the switch from the pure electric mode to the hybrid driving mode. This paper studies the mode switching process involved in the power-split hybrid electric vehicle driving process, and a nonlinear dynamic equation of the electromechanical coupling of the corresponding transmission system is established. Then the multi-scale method is employed to solve the dynamic equation, and the amplitude-frequency response curve is drawn. According to the curve, the effects of load, mechanical input excitation of the engine and motor electromagnetic excitation on the electromechanical coupling torsional vibration of the transmission system are studied. The engine and motor torque distribution schemes are obtained by analyzing the amplitude-frequency response curve of the torsional vibration characteristics of the system. The analysis results show that the vibration instability phenomenon of the transmission system can be avoided by establishing the nonlinear dynamic equation of the transmission system, analyzing the vibration characteristics of the vibration system, and optimizing the torque distribution of a PS-HEV at different working modes.