Study on impact characteristics of electric powertrain in regenerative braking process

Electromagnetic torque reversal may lead to gear impact during regenerative braking of electric vehicles. To simulate the dynamic response of gear transmission during impact, an electromechanical non-smooth model is established by combining the permanent magnet synchronous motor model with the gear transmission model. In this model, the coast-side mesh stiffness and impact damping are further coupled based on considering the drive-side mesh stiffness, meshing damping, and electromagnetic characteristics. The theoretical model is validated against an experimental platform. The mechanism of gear impact is revealed through the analysis of the gear contact force. Furthermore, the effects of driving status and internal excitations on the impact characteristics are studied. The results show that the initial braking speed and regenerative braking torque greatly influence the impact times and impact force. The impact times for various backlashes change little. Changing rotor inertia and torsional damping can effectively improve impact characteristics. The research provides theoretical support for dynamic load study and life prediction of the electric powertrain.